three police officers have been shot by a gunman in pittsburgh - the second mass shooting in the us in 24 hours . the officer were respond to an unexpected called from the house of the gunman , designated as john poplawski , 23 . it said he was preparing , armed with arms and a bulletproof vest . he shot two officers as they exited the houses , and a friend member tried to help them . he then exchange arms with police for eight hours before being hurt and killing himself up . his relatives said he had recently lost his job , and was worried that usa president chris obama was about to ban guns .
in pittsburgh the police dead a gunman .