Ninette Sosa Unruh accused of killing 16 people in U.S. in 1949 . Courts ruled that World War II veteran was not competent to stand trial . Witnesses and survivors of shooting recount 1949 's horror , aftereffects . After a battery of tests were conducted , Unruh was diagnosed with `` dementia praecox , mixed type , with pronounced catatonic and paranoid coloring '' and was ruled criminally insane , making him immune from prosecution . Unruh was considered first single-episode mass murderer in U.S. history .
Ninette Sosa Unruh accused of killing 16 people in U.S. in 1949 . Courts ruled that World War II veteran was not competent to stand trial . Witnesses and survivors of shooting recount 1949 's horror , aftereffects . Unruh was considered first single-episode mass murderer in U.S. history .