The suspect who opened fire at a bank in downtown Louisville, Kentucky, and killed four people on Monday morning is believed to be a previous employee, Louisville Metro Police Deputy Chief Paul Humphrey said.
"We believe this is a lone gunman who did have a connection to the bank," he said.
Officers responded to the mass shooting within three minutes of being dispatched and found the suspect still firing, he said. They exchanged gunfire with the suspect, who died at the scene, although it was unclear if he was killed by an officer or died of a self-inflicted gunshot.
Four people were found dead inside, and eight people are being treated at the hospital, including at least two officers who were shot.