They also study physical security devices, sequestered juries, prisoners in court, controls on grand jury materials, working with sensitive information, and the basic elements of the WITSEC program.
To date the WITSEC program, in which participation is voluntary, has given over 5,200 witnesses new identities and new live.
For a witness to participate in WITSEC, he or she must first be sponsored by a US attorney of the district in which the prosecution will take place.
Another factor that makes managing the WITSEC a great challenge is the witnesses themselves.
The Marshals Service's 165 WITSEC specialists, who work in undisclosed locations around the nation, average eight cases each.