Aside from the fact that authorities were warned in advance about him, we need to recognize the danger that prescription drugs pose.
Especially selective serotonin reuptake inhibitors

1. Conclusions
   There are many reports and studies confirming that SSRI antidepressants can cause violence, suicide, mania and other forms of psychotic and bizarre behavior. Overall, the SSRIs produce violence, suicide and extremes of abnormal behavior by a variety of mechanisms.
   Source