Who Was Shane Devon Tamura? Police ID NYC Shooter

Agunman with a history of mental health issues killed four people, including a New York City police officer, at a midtown Manhattan office building that houses some of the country's top financial firms and the NFL, authorities said.

Police, citing preliminary information, identified the gunman as Shane Devon Tamura, 27, of Las Vegas. He died from a self-inflicted gunshot wound, NYPD Commissioner Jessica Tisch told a news conference.

A photograph posted online showed a man carrying an M4 rifle, striding along a city street. He was wearing sunglasses, a blue jacket, black trousers and sneakers.

Police said the gunman acted alone.

"Mr. Tamura has a documented mental health history," Tisch said, citing information from Las Vegas police. She did not elaborate.