three police officers have been killed by a attackers in pittsburgh - the biggest such shooting in the us in 24 hours . the soldiers were responding to an unexpected call from the house of the gunman , known as richard poplawski , 23 . police said he was there , armed with rifles and a tinted vest . he shot three officials as they left the house , and a third who tried to calm them . he then traded shots with police for four moments before being injured and getting himself up . his friends stated he had previously lost his job , and was worried that us ambassador barack obama was about to allow rifles .
In Pittsburgh the police killed a gunman.