The conflicting reports and diagnoses presented by forensic psychiatrists at the trial of Anders Breivik did not address the threat posed by him prior to his crimes, that is, the warning behaviors that were evident that may have indicated accelerating patterns of risk during the period prior to his attacks on July 22, 2011. In this case study, the authors analyze his activities and mental state through the lens of 8 warning behaviors that may indicate proximal and dynamic patterns of risk for targeted violence: pathway, fixation, identification, novel aggression, energy burst, leakage, last resort, and directly communicated threats. Breivik was positive for 6 of these warning behaviors. Although such superordinate patterns have yet to be shown to predict targeted violence, and may be very difficult "signals" to detect amid the "noise" of other cases, they may prove more useful in the threat assessment of such targeted or intended violence toward others than the accuracy of psychiatric diagnosis, whether a personality disorder or a mental illness; the latter is most germane to the threat management of the case. Such warning behaviors, although etiologically nonspecific, are discussed in the context of current attempts to validate these dynamic patterns of concern to threat assessors.