The FBI loves its acronyms! And since many of my characters work for the Bureau, so do I! But what do they all mean? Here’s your cheat sheet:

ADIC – Assistant Director in Charge. Most FBI field offices are run by an SAC (Special Agent in Charge), but the biggest field offices are run by ADICs.

ASAC – Assistant Special Agent in Charge. Working directly under the SACs (Special Agents in Charge) who run divisions or field offices, the ASACs run programs.

BAU – Behavioral Analysis Unit. The BAU is where FBI “profilers” (the official name is Criminal Investigative Analysts) work. BAU is a part of CIRG (Critical Incident Response Group) and is located at Aquia. BAU agents provide behavioral-based support to the FBI, as well as other federal, and state, local and international law enforcement agencies, including profiles of unknown subjects (UNSUBs).

CARD – Child Abduction Rapid Deployment Team. These teams are located across the country, and consist of experienced child abuse investigators at the FBI.

CIRG – Critical Incident Response Group. CIRG provides rapid response for crisis situations around the country and integrates tactical, negotiations, behavioral analysis, and crisis management resources. The BAU (Behavioral Analysis Unit) and HRT (Hostage Rescue Team) are part of CIRG.

CNU – Crisis Negotiation Unit. Also part of CIRG (Critical Incident Response Group), CNU trains the FBI’s field office negotiators and deploys with HRT to domestic crises. CNU’s motto is Pax Per Conloquium (Resolution Through Dialog).

ERT – Evidence Response Team. ERT agents are specially trained FBI agents who collect evidence at crime scenes. Being on ERT is a secondary position, so these agents also work regular Special Agent duties.

HRT – Hostage Rescue Team. Also part of CIRG (Critical Incident Response Group), HRT is part of the FBI’s tactical response for crises. Unlike SWAT, their members work full-time as HRT agents and respond to incidents involving hostage rescue, barricaded subjects, and high-risk arrests. Their motto is Servare Vitas (To Save Lives).

LEGAT – Legal Attache. The FBI has approximately 67 LEGATS, who work overseas in Embassies. LEGATS work with law enforcement and security agencies in their host countries to coordinate investigations.

NCAVC – National Center for the Analysis of Violent Crime. The NCAVC consists of all the units of BAU, plus the Behavioral Research and Instruction Unit. They also run ViCAP (the Violent Criminal Apprehension Program, a database to link crimes across the country).

OPA – Office of Public Affairs. The FBI has an OPA at every field office, which is in charge of managing the portrayal of the FBI and handling community outreach, media inquiries, and press releases.

OPR – Office of Professional Responsibility. OPR reports directly to the Deputy Director of the FBI. Its role is to identify misconduct within the FBI and manage investigations and discipline related to misconduct.

RA – Resident Agency. The FBI has 56 field offices across the U.S. and in Puerto Rico, and approximately 380 Resident Agencies, smaller FBI offices spread across the country.

SA – Special Agent. Special Agents investigate violations of federal laws, and assist state and local law enforcement. There are more than 13,000 Special Agents (as part of more than 35,000 FBI employees).

SAC – Special Agent in Charge. SACs run field offices (with the exception of the largest offices – LA, NY, and DC, which are run by ADICs because of their size). Within the bigger offices, SACs run divisions under the ADIC. SACs also lead special groups, such as HRT.

SSA – Supervisory Special Agent. SSAs run squads. Each field office of the FBI has numerous squads, broken up by type of investigation (white collar, intelligence, counter-terror, violent crime, etc.).

SWAT – Special Weapons and Tactics. All of the FBI field offices have SWAT teams and Special Agents who are SWAT members do so as an ancillary duty (in addition to work on a regular squad). SWAT agents handle high-risk tactical operations.

UNSUB – Unknown Subject. UNSUBs are targets of investigations where the person who committed the crime is not known by name.

ViCAP – The Violent Criminal Apprehension Program is a special database used to link crimes that are geographically dispersed. Local and state law enforcement can enter crimes into the database and it is searchable by terms, so crimes can be connected by details. ViCAP has been used to link many serial crimes since its inception. It also lists missing and unidentified persons databases.