With our partners in the law enforcement and intelligence communities, the FBI worked thousands of investigations during 2013, from cyber crimes to espionage and multi-million-dollar fraud schemes. As the year draws to a close, we take a look back at some of 2013’s most significant cases.

Part 1 focused on terrorism. Part 2 highlights top cases—in reverse chronological order—from the FBI’s other investigative priorities:

Silk Road seizure: In October, $28 million worth of virtual money called bitcoins was seized from the owner and operator of the Silk Road website—an illegal global cyber business designed to broker criminal transactions. 

Navy Yard tragedy: In September, the FBI responded to the shootings at Washington’s Navy Yard and later released its findings about the shooter, Aaron Alexis, along with photos and video.

Operation Cross Country: In July, 105 juveniles were recovered—and more than 150 pimps arrested—in the seventh nationwide operation targeting underage prostitution. The three-day sweep took place in 76 cities and was carried out by the FBI in partnership with local, state, and federal law enforcement agencies and the National Center for Missing & Exploited Children as part of the Bureau’s Innocence Lost National Initiative. 

Health care fraud: In May, the FBI’s Medicare Fraud Strike Force charged 89 individuals—including doctors, nurses, and other licensed medical professionals—for their alleged participation in Medicare fraud schemes involving approximately $223 million in false billing. 

Drug trafficking, money laundering: In May, four individuals were convicted in a sophisticated conspiracy to launder millions of dollars in illicit Los Zetas drug trafficking proceeds by purchasing, training, breeding, and racing American quarter horses in the U.S. 

Conspiracy to commit espionage: A former U.S. federal employee was indicted in May for conspiracy to commit espionage for Cuba. The individual allegedly helped Cuba’s intelligence service recruit and insert a spy into the U.S. Defense Intelligence Agency. 

Public corruption: In March, former Detroit mayor Kwame Kilpatrick, his father, and a prominent city contractor were convicted of racketeering, extortion, bribery, fraud, and tax charges related to Kilpatrick’s long-running criminal enterprise while in office. 

Credit card scam: In February, 18 individuals were charged for allegedly creating thousands of phony identities to steal at least $200 million in one of the largest credit card fraud schemes ever charged by the federal government. 

Alabama bunker standoff: In January, a man held a 5-year-old boy captive for nearly a week in an underground bunker in Alabama. Working together with state and local law enforcement, members of the FBI’s Hostage Rescue Team eventually entered the bunker and rescued the child. 

Cyber crime: In January, three alleged international cyber criminals were charged in New York with creating and distributing the potent Gozi virus, which infected more than a million computers worldwide and caused tens of millions of dollars in losses.