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Handwriting, Typewriting, Shoeprints, and Tire Treads, by Held (Forensic Science Communications, April 2001)

Handwriting, Typewriting, Shoeprints, and Tire Treads, by Held (Forensic Science Communications, April 2001)


April 2001 - Volume 3 - Number 2

Research and Technology

Handwriting, Typewriting, Shoeprints, and Tire Treads:
FBI Laboratory’s Questioned Documents Unit

Dorothy-Anne E. Held

Questioned Documents Examiner
Questioned Documents Unit
Federal Bureau of Investigation
Washington, DC

Introduction | Physical Examinations | Comparison Examinations
Reference and Standards Files
| Protocols for a Typical Case
 Training of FBI Questioned Document Examiners | References


Questioned Documents Unit (QDU) personnel at the FBI Laboratory support federal, state, local, and international law enforcement agencies by providing advanced technical and forensic support with the following:

  • Examinations, reports, and testimony;

  • Technical support of field investigations;

  • Training provided to FBI and other federal and state examiners; and

  • Research and evaluation of newly developed technology.

Physical Examinations

Physical examinations in the QDU involve close and careful scrutiny of surfaces and other items. Paper is the most typical surface examined. Examiners may focus on one or more of the following:

  • Something on the surface, such as handwriting, typewriting, alterations, or obliterations;

  • Something in the surface, such as indented writing, watermarks, or safety fibers; and

  • Damage to the surface, such as torn edges, moisture, or charring.

To determine whether watermarks or other internal features are present in paper, evidence is placed over a source of transmitted light. The presence of a watermark is important, because it can sometimes be used to establish a date that the document cannot precede. For example, if a document is dated 1959, but the watermark was not produced until 1965, the date written on the document is incorrect.

Two methods for determining the presence of indented writing are used. They are side lighting, in which a light source is passed over the sheet of paper at an oblique angle, and the electrostatic detection apparatus (ESDA), an instrument that renders indented writing visible and provides a record of the writing. See Figure 1.

The Video Spectral Comparator 2000 (VSC2000; Foster+Freeman, Worcestershire, United Kingdom) is used for a variety of physical examinations including determining the presence of indented writing, deciphering writing, rendering obscured writing visible, and differentiating between inks and papers by their optical properties. For more information about the VSC2000, see “Advances in Document Examination: The Video Spectral Comparator 2000,” by Mokrzycki in the October 1999 issue of this journal. See Figure 2.

Other physical examinations of the QDU include determining the contents of used carbon paper and typewriter ribbons, stabilizing and examining burned or moisture-damaged paper, and reconstructing torn or shredded paper.

Murder of Heather Lee Sims
On April 30, 1989, law enforcement officers were called to the Alton, Illinois, home of Paula and Robert Sims. The couple claimed that Mrs. Sims had been knocked unconscious by an unknown intruder who then kidnapped their 6-week-old daughter, Heather. Although Mrs. Sims exhibited no evidence of injury, and the physical characteristics in and around the home did not support their narrative, the incident was initially treated as a kidnapping.

Heather’s body was later discovered in a plastic bag in a trash can. Investigations revealed that this was the second infant the Sims’ family had lost under similar circumstances. Three years earlier, 13-day-old Loralie was found dead in a wooded area behind the Sims’ home after a reported kidnapping. Although her parents were suspected of foul play, there was insufficient evidence to charge them at that time.

The questioned documents examination centered on the plastic bag. An FBI questioned documents examiner visited the plastic bag manufacturing plant and consulted with the personnel concerning what might constitute defining characteristics for a suspect bag. The cut edges were not suitable for this purpose. However, it was determined that the heat-seal process used during manufacturing imparted individual characteristics to the bags. These factors provided a framework by which individual bags could be definitively linked and placed within a specific period of time. It was, therefore determined that the plastic bag that contained Heather’s body and the bags found in the Sims’ home were manufactured by the same machine within seconds of each other.

Paula Sims was charged with killing Heather by suffocation. She was convicted of murder on February 2, 1990, and sentenced to life in prison without parole. See Figure 3.

Photograph of a ledger page with indented writing. Special photographic techniques can be used to enhance indented writing (top) using side lighting and special film.

Enlarged photograph of the ledger page that shows the apparent bank robbery note that was produced from the indented paper, which may link an individual to the note given during the robbery.

Figure 1. Special photographic techniques can be used to enhance indented writing (top) using side lighting and special film. The second photograph shows the apparent bank robbery note that was produced from the indentations in the paper, which may link an individual to the note given during the robbery.

Photographic images of shredded paper produced using the VSC2000 and ambient white light. The shreds have differing luminescent intensities that may help the examiner sort the pieces.

Figure 2. Image of shredded paper produced in ultraviolet radiation using the VSC2000 (right) and under ambient white light (left). Notice how the shreds have differing luminescent intensities that may help the examiner sort the pieces. Click for enlarged image.

Trash bags from the Sims' household

Comparison of trash bags.

Comparison of machine marks on trash bags

Figure 3.
Photographs from the Heather Lee Sims murder investigation: trash bags from the Sims’ household (top); comparison of trash bags (middle); and machine marks on trash bags (bottom).

Comparison Examinations

Evaluations and comparisons of questioned (unknown origin) and known materials comprise the second type of examination conducted by FBI questioned document examiners. Comparisons are conducted on handwriting, hand printing, typewriting, and typewriter components including typewriter ribbons and elements. Less frequently, comparisons of photocopies, facsimiles, printers and printing processes, checkwriters, dry seals or stamps (rubber or similar types), and other items of evidence are requested.

Handwriting Comparisons
The majority of the cases handled by the QDU involve handwriting. Although not all handwriting is identifiable to a specific writer or writers, the examination of handwriting characteristics can sometimes result in determining the origin or authenticity of said questioned writing. Traits such as age, sex, personality, or intent cannot be determined from handwriting examinations.

Handwriting comparisons are based on the principles that no two people write exactly alike and that characteristics reoccur throughout every person’s writing, although no one writes exactly the same way twice. This combination of characteristics is unique to every individual and is used by document examiners for comparison.

Evidence bearing writing may be received in two forms. If the evidence submitted includes only writing of unknown origin, the examination will probably include only file searches, the preservation of a visual record, and an evaluation of the potential for future comparisons of the writing. When both questioned and known (the product of a specific, identified individual) writings are submitted, the same file searches and preservation are completed. In addition, a side-by-side comparison of the writings will occur. At the conclusion of any QDU examination, a report is issued explaining the examinations conducted and stating any definitive determinations made as a result of the comparisons.

A definite opinion is not always possible when conducting a handwriting comparison. Reasons for an inconclusive result include the following.

  • The questioned writing is limited.

  • The known writing is limited in amount, comparability, or both.

  • The writing is not naturally prepared.

Common types of writing unlikely to yield definite opinions include photocopies (often mistaken for original writing) and deliberately distorted writing, including tracings and simulations. Figures 4 and 5 include some questioned signatures that contain characteristics indicative of distorted writing. Because distorted writing does not usually reflect the normal habits of the person who prepared it, handwriting comparisons are unlikely to result in the association of a questioned signature with the person who wrote it.

Reduced image of an oil stock certificate that features genuine signatures of the oil company officers. Image of the genuine signature of the oil company's treasurer, as it appears on the oil stock certificate.

Image of the genuine signature of the oil company's president, as it appears on the oil stock certificate.

Figure 4.
The certificate and signatures in these three photographs are genuine.
Questioned signature of the oil company treasurer as signed on an oil stock certificate.

Questioned signature of the oil company treasurer as signed on an oil stock certificate.

Questioned signature of the oil company treasurer as signed on an oil stock certificate.
Questioned signature of the oil company president as signed on an oil stock certificate.

Questioned signature of the oil company president as signed on an oil stock certificate.

Questioned signature of the oil company president as signed on an oil stock certificate.

Figure 4 (continued).
The identity of the author of the other certificate signatures in the set of six photographs above is in question. The questioned signatures also contain characteristics of simulations or tracings. Some of the characteristics include tremor, poor line quality, blunt ending and beginning strokes, and unnatural pen lifts in the signatures.

Signed photograph of professional baseball player Mickey Mantle in uniform and holding a bat.
Genuine signature of professional baseball player Mickey Mantle.

Simulated signature of professional baseball player Mickey Mantle.

Traced signature of professional baseball player Mickey Mantle.

Figure 5.
Mickey Mantle’s genuine signature is shown top right. The next signature, middle right, is an attempt to imitate Mickey Mantle’s signature by means of simulation, which is created by copying an actual model or a mental image of a genuine signature. The third signature, below right, is a traced signature executed by actually following the outline of a genuine signature or overlaying a genuine signature and using transmitted light to follow the line of writing.

Peter Weinberger Kidnapping
On July 4, 1956, one-month-old Peter Weinberger was kidnapped from his home in Westbury, Long Island, New York (Dorman 1998). A ransom note scrawled in green ink on a sheet torn from a student notebook was left in his baby carriage. The note said, “Attention, I’m sorry this had to happen, but I am in bad need of money, & couldn’t get it any other way. Don’t tell anyone or go to the police about this, because I am watching you closely. I am scared stiff, & will kill the baby at your first wrong move . . . Your baby sitter.” See Figure 6.

Handwriting experts from the FBI Laboratory went to New York to participate in the investigation. The examiners found the ransom note contained distinguishing characteristics in 16 letters of the alphabet. Most unusual was the kidnaper’s lower-case script “m,” which resembled a sideways “z.” Investigators searched through nearly two million handwriting specimens from public records trying to find similar writing.

Handwriting from the first Weinberger kidnapping ransom note.

Handwriting from the second Weinberger kidnapping ransom note.

Sample of known handwriting by Angelo LaMarca, later identified as the author of the Weinberger kidnapping ransom notes.

Sample of known handwriting by Angelo LaMarca, later identified as the author of the Weinberger kidnapping ransom notes.

Figure 6.
Signatures from the Weinberger kidnapping case. From top to bottom, the photographs show signatures from the first and second ransom notes, and the third and fourth signatures are the known handwriting of Angelo LaMarca.

On July 10, the Weinbergers were instructed by telephone to put the ransom money in a blue bag. The bag would be left by a parkway exit sign. A second note was in the bag, repeating the $2,000 demand. The handwriting seemed to match the first note.

Meanwhile, a federal probation office in Brooklyn discovered in his files a document written by a criminal defendant who formed the letter “m” in the same way as the author of the ransom notes. The writer was Angelo LaMarca, a 31-year-old auto mechanic. Questioned document examiners compared the document and the notes. LaMarca was identified as the author of the ransom notes.

LaMarca admitted kidnapping and abandoning the Weinberger child and took investigators to the place where he had left the child. Little Peter Weinberger had died of exposure.

LaMarca was indicted on charges of kidnapping and first-degree murder. He was found guilty on both counts and executed at Sing Sing Prison in Ossining, New York, on August 7, 1958.

Typewriter, Typewritten Text, and Typewriter Ribbon Comparisons
Typewriters, of which there are two basic types, are machines that put an image on paper using hard type. The kind of typewriter (and ribbon) used to prepare a questioned document suggests the examinations possible and may limit the conclusions possible as a result of the examinations. See Figure 7.

A typebar typewriter is one in which the typeface elements are permanently fastened into the machine. Because each machine has permanent, nonremovable typeface components, text can sometimes be associated to the specific machine used by comparing characteristics, such as typeface damage or alignment defects, in the text and machine.

The other type of typewriter has typeface that is affixed to an interchangeable element: a ball, printwheel, or (rarely) thimble. The style of type is specific to the individual element, not to the machine. Therefore, although text may be associated with a specific element, it can rarely be associated with a particular machine.

When examining text from a single element typewriter, ribbon-related examinations and comparisons become very important. There are two general kinds of typewriter ribbons: fabric, which does not retain a legible image of the texts prepared using it; and carbon, which can retain readable text. The two kinds of correction ribbon (lift-off and cover-up) used on typewriters also retain images that can be compared with text and carbon ribbons. Defects of the typeface may also be apparent from a ribbon. The QDU maintains a ribbon analysis workstation, an apparatus used to transcribe the text on typewriter ribbons.

Occasionally, QDU typewriter examinations may include a paper fiber-transfer comparison. The low-density polyethylene backing on typewriter ribbons is delicate and assumes the imprint of fibers in the paper. Using a comparison microscope, the voided areas of typewriter ribbons can be associated (by means of these fiber impressions) with the paper on which the text has been imprinted. See Figure 8.

Unabomber Typewriter Examination
On September 19, 1995, The Washington Post published the Unabomber’s 35,000-word manifesto. David Kaczynski, a social worker in upstate New York, contacted authorities because he thought the document exhibited similarities to his brother’s writings. This important tip led to the arrest in April 1996 of Theodore J. Kaczynski, the terrorist who during a 17-year period constructed bombs that killed 3 and injured 22 people (Johnston 1998).

During the arrest, FBI agents discovered an isolated cabin in Montana filled with evidence. The evidence included handwritten journals, logs, and an uncompleted autobiography. Three typebar typewriters were also found in the cabin. See Figure 9. Approximately 400 typing examinations were done in the Unabomber case. Other questioned document comparison examinations in the case included handwriting, envelopes, labels, and rubber stamps.

On January 23, 1998, Mr. Kaczynski pleaded guilty to all the federal charges against him and acknowledged he was the Unabomber who killed and maimed people with package bombs. He was sentenced to life in prison without the possibility of release.

Sample typewriter standards file that is used to determine the make, model, and other information concerning the typewriter used to prepare documents in question.

Typewriter type specimens from a particular typewriter.

Figure 7.
A typewriter standards file (click for enlarged image) is used to determine the make, model, and other information concerning the typewriter used to prepare documents in question. The photographs above show typewriter type specimens from a particular typewriter.

Typewriter type specimens from a particular typewriter.

Figure 7 (continued).
The sample type specimens in the top two photographs are compared to this typewritten message from an unknown source. Click for enlarged image.

Example of paper fiber transfer with typewritten text.

Example of paper fiber transfer with the carbon ribbon impression.

Figure 8.
Example of paper fiber transfer with typewritten text (top) and the carbon ribbon impression (bottom).

The typewriter identified with correspondence from the UNABOM case.

Enlargement of the unique characteristic of the typed letter   Enlargement of the unique characteristic of the

Figure 9.
The typewriter (top) identified with correspondence from the UNABOM case. Note the unique characteristic of the typed letter “u” (bottom left) from the questioned document, which matches the unique characteristic of the “u” typewriter key (bottom right) from the typewriter seized during the investigation.
Shoeprint and Tire Tread Examinations
Shoeprint and tire tread impression evidence is examined to determine the brand name and manufacturer of the shoe or tire that made an impression. The design of the shoe’s outsole may be searched through the Shoeprint File. The portions of an impression that may be analyzed include designs, borders, and general shapes (e.g., pointed or rounded toes). If the impression is complete, a general estimation of size sometimes can be made. A more precise size determination is possible if the manufacturer is known. See Figures 10 and 11. Similarly, tire tread impression evidence is searched through the Tire Tread File or through the annual reference book, Tread Design Guide (Tire Guides, Incorporated, 2000).
Photo of bloodied shoeprint on tile flooring.  heldf11.jpg

Figure 10 (left).
Bloodied shoeprint on tile flooring.

Figure 11 (right). Shoeprint on an individual’s skin seen as bruising.

Comparisons of shoeprint and tire tread impression evidence with submitted shoes or tires are also conducted. Impression evidence can be in the form of photographs, lifts, casts, or an original item bearing an impression. A shoe can be definitively identified with an impression if there is sufficient detail in the impression and sufficient identifying characteristics are on the shoe. A tire can be positively identified with an impression if the same criteria are met. See Figure 12.

Bodziak (2000) offers the following comment on this form of evidence:

Shoes are fascinating items of clothing. They are made in a variety of ways and in thousands of designs. In turn, each design is made in many distinguishable sizes. As the outsole wears, their design and other characteristics steadily change. They acquire cuts, scratches, nicks, and other characteristics of a random nature. These traits serve to give them a tremendous degree of individuality. As they track through soil, snow, sand, residue, and other materials, supporting the weight of their wearer, they impress their distinct and individual features on or into the surfaces over which they pass.

A Goodyear Invicta® GL tire.  Test tire impression from a Goodyear Invicta® GL tire
Questioned tire impression in soil and gravel.

Figure 12.
A Goodyear Invicta® GL tire (top left) from which a test impression (top right) was made to compare with a questioned impression (bottom).
Items of footwear and their impressions that remain at the crime scene offer sound, reliable, and demonstrative evidence of a person’s presence. (p. vii; quoted with permission of author)

Shoeprint Investigation of the Simpson–Goldman Murders
Following the murders of Nicole Brown Simpson and Ronald Goldman in the summer of 1994, photographs depicting shoeprint impressions in blood from the Brentwood, California, crime scene were delivered to the FBI Laboratory. The Los Angeles Police Department requested the determination of the brand and size of footwear that made the impressions. The impressions submitted were mainly from a path adjacent to the home of one of the victims, Nicole Brown Simpson. However, other partial impressions were on the victims’ clothing.

By examining these impressions and researching the FBI reference and standards files, an FBI examiner was able to positively link some of the crime scene impressions to size 12 Bruno Magli Lorenzo shoes. The examiner issued a report directly to the judge in the case and was subsequently called to testify. Although the shoeprints from the crime scene could be positively linked to a particular brand and size of shoe, at the time of the criminal trial no evidence was available that defendant O. J. Simpson owned such shoes. In the interval between the criminal and civil trials, pictures depicting Mr. Simpson in such shoes were discovered. The shoes became evidence in the civil trial, when the examiner restated his testimony (Bodziak 2000, pp. 431-458).

Reference and Standards Files

To aid in physical and comparison examinations, the QDU maintains the following files that are divided into two types:

  • Reference Files: Repositories for information drawn from casework, which are used to relate incoming data to previously examined material, for example, to make an association between two threatening notes.

  • Standards Files: Repositories for manufacturers’ and similar primary-source data, which are used to determine the source of an item of evidence, for example, the maker of a style of typeface.

Anonymous Letter File and Bank Robbery Note File: Contain information about and images of threatening letters or messages (meeting certain criteria) and notes used during bank robberies and some extortion cases.

Checkwriter File: Provides a variety of sources (references) for determining the manufacturer or defining characteristics (standards) of checkwriter apparatus or both. This file also contains some case materials.

National Fraudulent Check File: Contains information pertaining to checks handled during QDU casework. This reference file includes sections devoted to signatures, company names, counterfeit checks, money orders, and travelers’ checks.

National Motor Vehicle Certificate of Title File: Contains examples of authentic certificates of title, as well as previously submitted fraudulent titles.

Office Equipment File: Consists of source materials regarding typewriters, printers, photocopiers, facsimiles, and related equipment. This file provides a means of classifying office equipment, as well as standards for comparison purposes.

Shoeprint and Tire Tread Files: Contain manufacturers’ information and information from previously submitted evidence. These standards files are used for determining the brand name and model of items having made an impression on evidence recovered at crime scenes.

Watermark File: Consists of reference information pertaining to watermarks and other paper-manufacturing matters and examples of unusual watermarks drawn from casework.

Protocols for a Typical Case

Evidence received: Ten checks bearing original signatures and endorsements (designated Q1 through Q10) and known writing from two individuals (designated K1 and K2).

Request: Handwriting comparison.

Preliminary administrative procedures must occur first. They include the following:

  • Acknowledging receipt of the evidence;

  • Checking the evidence against the incoming communication (to ensure consistency);

  • Assigning unique identifying numbers to the submissions (denoting whether it is questioned or known); and

  • Making arrangements for any other requested examinations such as DNA analysis or fingerprint comparisons.

A listing of the evidence is then recorded on a Laboratory worksheet, and a visual, scanned record is prepared.

Typically, checks are side lighted for possible indented writing. The ESDA is used only when specifically indicated.

Examinations of checks often begin with the identification and evaluation of the
printing processes used. Are they consistent with one another and with genuine checks? If printing process anomalies are observed, the checks may be counterfeit. Other physical features of checks that interest document examiners are the safety features (watermarks), microprinting (usually in the signature line or as a border), and the type of checkwriter (if any) used.

The handwriting on the checks will be evaluated for suitability for comparisons. The known writing will be examined separately to determine whether it is original, comparable to that on the checks, and sufficient in quantity for viable comparisons. If these criteria are met, a side-by-side comparison of the questioned and known writing is undertaken.

File searches for checks are conducted in the National Fraudulent Check File: always in the signature and company name sections, and, if applicable, in other specific portions of this file. Printing processes are sometimes searched in the Office Equipment File, and the Checkwriter File may be accessed, if applicable.

How FBI Questioned Document Examiners Are Trained

Applicants to the FBI QDU examiner training program must meet all FBI employment requirements. In addition, an applicant must be a college graduate and willing to respond to knowledge, skills, and ability questions. The physical requirements include acute vision, no color blindness, and the ability to lift at least 50 pounds.

The training consists of a two-year, collegiate-style program that includes formal classroom training and actual document examinations, conducted under the guidance and evaluation of experienced document examiners. Some of the classroom portions of the training may be abridged if the individual has substantive prior experience as a document examiner. At least five moot courts are administered to each applicant as a condition of certification.

After completing this training program, each trainee must be capable of independently conducting nondestructive forensic examinations on documentary evidence that result in accurate opinions and presenting findings as an expert witness in formal legal proceedings.

Additional information on the forensic examination of questioned documents, shoeprints, and tire treads is available in the Questioned Documents Examinations and the Shoeprints and Tire Treads Examinations sections of the Handbook of Forensic Services.

For more information about the Questioned Documents Unit, call or write:

Federal Bureau of Investigation
Questioned Documents Unit
Room 10861
935 Pennsylvania Avenue NW
Washington, DC 20535-0001
Telephone: 202-324-4454
Facsimile: 202-324-6134


Bodziak, W. J. Footwear Impression Evidence: Detection, Recovery, and Examination. 2d ed., CRC Press, Boca Raton, Florida, 2000. Available at http://www.crcpress.com/

Dorman, M. Our story: Held for ransom: A kidnapping in Westbury set off an intense manhunt as the country awaited word of a child’s fate, Newsday, June 1, 1998.

Johnston, D. 17-year search, an emotional discovery and terror ends, New York Times, May 5, 1998.

Lockwood-Post’s Directory of the Pulp, Paper and Allied Trades (North American Edition). Miller Freeman Co., San Francisco, California, 2000. Available at http://www.pulp-paper.com/

Mead Corporation. Paper Knowledge. Mead Corporation, Dayton, Ohio, 1990. Available at http://www.mead.com/

Mokrzycki, G. M. Advances in document examination: The Video Spectral Comparator 2000, Forensic Science Communications [Online] (October 1999). Available: http://www.fbi.gov/programs/lab/fsc/backissu/oct1999/mokrzyck.htm

Polk’s Motor Vehicle Registration Manual. R. L. Polk and Co., Detroit, Michigan, 1990.

Tire Guide. Tire Guides, Inc., Boca Raton, Florida, 2000. Available at http://www.tireguides.com/

Tread Design Guide. Tire Guides, Inc., Boca Raton, Florida, 2000. Available at http://www.tireguides.com/

Vastrick, T. W. Classification and Identification of Checkwriters. American Board of Forensic Document Examiners, Inc., Houston, Texas, 1991. Available at http://asqde.org/

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