In major bomb incidents, such as the bombings of the World Trade Center and of the Federal Building in Oklahoma City, many agencies are involved in the investigation, including local law enforcement and fire agencies, the Bureau of Alcohol, Tobacco, and Firearms (ATF), and the Federal Bureau of Investigation, in the World Trade Center case, the Port Authority police provided security. Public safety following a bombing is imperiled even further than the obvious consequences due to the danger of a secondary device and structural weaknesses at the site that could cause further casualties. Rescue personnel, to help in the crime investigation, need to log the location from which each victim is removed and save clothing and other evidence. Both the FBI and the ATF teach similar post-blast investigative methods, using a team comprised of a photographer, sketch artist, searchers, and evidence technician. The scene must be heavily documented before any physical activity is conducted. Some of the most important evidence will be collected from the vehicle that usually acts as a container for the explosive device. Finally, close liaison must be maintained between the crime scene searchers and the interview teams.