In 2014, the FBI published a report titled A Study of Active Shooter Incidents in the United States Between 2000and 2013.2 One hundred and sixty active shooter incidents in the United States occurring between 2000 and 2013were included in the sample. In this first report, the FBI focused on the circumstances of the active shootingevents (e.g., location, duration, and resolution) but did not attempt to identify the motive driving the offender, nor did it highlight observable pre-attack behaviors demonstrated by the offender. The 2014 report will bereferred to as the "Phase I" study.The present study ("Phase II") is the natural second phase of that initiative, moving from an examination ofthe parameters of the shooting events to assessing the pre-attack behaviors of the shooters themselves. Thissecond phase, then, turns from the vitally important inquiry of "what happened during and after the shooting"to the pressing questions of "how do the active shooters behave before the attack?" and, if it can be determined,"why did they attack?" The FBI's objective here was to examine specific behaviors that may precede an attackand which might be useful in identifying, assessing, and managing those who may be on a pathway to deadlyviolence