An officer sees the worst side of life every day. He is constantly exposed to society's underbelly. It can be difficult to maintain a view that there are any decent people out there. This is somewhat complicated since an officer faces potential danger on a daily basis. However, if an officer finds himself in a situation that focuses him on his vulnerability and lack of control, a critical incident stress reaction can be triggered.
Victim is known to responder.
Seeing death and tragedy is bad enough. If the officer finds he knows the victim, this can trigger a critical incident stress reaction. The symptoms may show up immediately after the incident. This is called an acute reaction. If symptoms are going to appear, this is as good a time for them as any.