Police in the US have said the gunman who killed a hostage and then himself in a stand-off at a NASA centre in Texas blamed his victim for a poor work performance review.
Authorities said 60-year-old William Phillips bought the gun on the same day last month that he printed off the bad review.
Phillips took the revolver to work at the Johnson Space Centre on Friday and shot dead fellow employee David Beverly who was 62.
Houston Police Chief Harold Hurtt said Phillips, a contract worker, initially wounded the NASA quality control engineer, Mr Beverly, with gunshots and then left the room.
However as Mr Beverly was trying to barricade a door to keep the shooter out, Phillips returned and killed his victim.
