The FBI's Communicated Threat Assessment Database: History, Design, and Implementation

Article excerpt

In January 1999, a gunshot pierced the window of a Pennsylvania house and killed the female resident. Her estranged husband, a wealthy doctor, was the prime suspect, but investigators did not have enough evidence to convict him. Early in the investigation, his attorney received two separate anonymous letters attempting to exculpate the husband. The investigators requested an authorial attribution analysis (i.e., an attempt to determine common authorship between two or more sets of communications) of the two anonymous letters and numerous ones written by the husband. Comparing these with the more than 1,000 letters contained at that time in the FBI's Communicated Threat Assessment Database (CTAD) strengthened the distinctive quality of the two sets of letters and their author. Investigators determined that the husband had sent the recent ones in an attempt to misdirect the investigation. During the interim, he had moved to Washington, and, in December 2002, authorities arrested him and returned him to Pennsylvania for trial. In 2004, FBI personnel provided expert testimony at the husband's trial as to the results of their analyses and the findings derived from CTAD. After a first-degree murder conviction, the judge sentenced him to life without parole.



The FBI's Behavioral Analysis Unit-1 (BAU-1) of the Critical Incident Response Group is a component of the National Center for the Analysis of Violent Crime at the FBI Academy and focuses its efforts on counterterrorism, threat assessment, and other forensic linguistics services. BAU-1 personnel offer services, including behaviorally oriented investigative assistance in counterterrorism matters, threat assessment/textual analysis, WMD, extortions, product tampering, arson and bombing matters, and stalking cases, to the FBI; other international, federal, state, and local law enforcement and intelligence agencies; and the military. In conjunction with these responsibilities, the unit implemented CTAD to serve as the primary repository for all communicated threats and other criminally oriented communications (COCs) within the FBI. It assists with categorizing, analyzing, assessing, and maintaining all communications falling into these two areas.

Some communicated threats and COCs are sent to their respective recipients for personal reasons, whereas others relate directly to criminal enterprises, such as extortion, kidnapping, and other crimes. Some fall under the domain of national security and have intelligence potential contained therein. For example, a communication to a corporation or a government entity could be an attempt to threaten, or actually violate, the security of the company or the United States.

All communicated threats and COCs received at the FBI are entered into CTAD, categorized accordingly, analyzed, and assessed for their respective threat potential. Then, BAU-1 agents search for similarities with other existing communications within the database, make a possible determination of authorship, and notify the submitting agency of their findings.


An increase from only several dozen per year in the mid-1990s to approximately 400 in 2005 alone aptly illustrates the significant rise in the number of threatening communications and COCs received by BAU-1 during the past several years. The advent of e-mail, with its ease of use and accessibility, has played an important role in this growth. Also, the terrorist attacks of September 11, 2001, and the anthrax mailings shortly thereafter, among other cases, have demonstrated the need for the FBI to monitor all of these communications. The agency, therefore, determined that a database would aid in coordinating this expanding number of communications and the requests for BAU-1 personnel to assess and analyze them.

During the early stages of planning, unit members envisioned a corpus with a word capacity exceeding 100 million, an extensive search potential, detailed categorization and classification parameters, and report-writing capabilities. …