February 6, 2019

Seeking Potential Victims in Robert Arnold Koester Case

The FBI is asking for the public’s assistance to identify potential victims of a suspected serial sexual predator who took nude photos of models and is alleged to have sexually assaulted many of these models, including individuals younger than 18 years of age. Robert Arnold Koester, also known as Bert Kay, Rhake Winter, and Qitooly, a 52-year-old U.S. citizen, has potentially been engaging in these criminal acts from 1994 through November 13, 2018. Victims have been identified in multiple cities across the United States. At the time of his arrest, Koester worked as a professional photographer, engaged in the photography of models, primarily on the West Coast of the United States.

If you have information about this ongoing investigation or believe you or someone you know may have been victimized by Robert Arnold Koester, the FBI requests that you complete this secure, confidential online questionnaire.

Identified victims may be eligible for certain services and rights under federal and/or state law. Please see the official press release below for detailed information on this investigation.


  • Robert Arnold Koester Case Victim Questionnaire
    Note: This questionnaire is only intended to collect information. Based on the responses provided, the FBI or a partner law enforcement agency will contact you for additional information if needed. 

Press Release:

Additional Resources:

Information from the public may also be submitted confidentially via email to: ModelCase@fbi.gov.

Robert Arnold Koester (2018 Carlsbad Police Department Photo)

Robert Arnold Koester, 2018 Carlsbad (California) Police Department photo

Robert Arnold Koester (2016 Oregon DMV Photo)

Robert Arnold Koester, 2016 Oregon DMV photo

Robert Arnold Koester (2010 California DMV Photo)

Robert Arnold Koester, 2010 California DMV photo