Shane Devon Tamura was the 27-year-old man living in Las Vegas who fatally shot at least four people in a mass shooting at 345 Park Avenue in New York City on July 28. Here's what to know about the N.

The gunman who killed four people, including a New York City police officer, during a shooting Monday inside a Manhattan skyscraper once refused to leave a Las Vegas casino, leading to his arrest, the 8 News Now Investigators have learned.

Shane Tamura is suspected of killing four people before shooting himself on the 33rd floor of the building at 345 Park Avenue, authorities said.

Four people were killed, including a police officer, and one was seriously injured when a gunman opened fire inside an office building before killing himself.

Follow along for live updates with the New York City shooting, where police investigate motive after five people, including the gunman, are killed in Monday shooting

Adams told reporters that investigators believe Shane Tamura of Las Vegas entered the building with the intent to reach the NFL 's offices but accessed the wrong set of elevator banks. "He seemed to have blamed the NFL ," Adams said. "The NFL headquarters was located in the building, and he mistakenly went up the wrong elevator bank."