Nigeria, July 29 -- On the evening of Monday, July 28, a mass shooting occurred at 345 Park Avenue, a high-rise office building in Midtown Manhattan, New York City.

A 27-year-old gunman, identified as Shane Devon Tamura of Las Vegas, entered the building with an assault-style rifle and opened fire.

The incident began around 6:30 p.m. (ET) when Tamura walked into the lobby of the skyscraper, which houses major firms including Blackstone, KPMG, and the NFL headquarters.

He shot NYPD Officer Didarul Islam, 36, who was working security, then fired at others in the lobby. Surveillance footage showed Tamura with a rifle in hand, sparing at least one woman in the elevator area.

He then took an elevator to the 33rd floor, where he killed anot...