A gunman opened fire inside a high-rise corporate building in the heart of Manhattan on Monday evening, killing a New York City police officer and three other people, officials said.
The suspected shooter acted alone and died from a self-inflicted gunshot wound, law enforcement officials told NBC News.
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The deadly gunfire, which was first reported about 6:30 p.m., was treated as an active shooting, prompting warnings and office evacuations, with lines of people seen leaving the building with their hands above their heads.
The gunman’s motive has not been disclosed.
Here’s what we know so far:
The victims
A New York City police officer, whose identity has not been made public was killed, three senior law enforcement officials said.
The officer’s family has been notified of the death.
Four civilians also died. Their names have not been released.
The gunman
Law enforcement officials said the violence was carried out by a lone gunman, who died from a self-inflicted gunshot wound.
The suspected shooter has been identified as Shane Devon Tamura, 27, of Las Vegas, according to four senior law enforcement officials.

In a photo three law enforcement officials shared with NBC News, the suspected gunman is seen walking into the midtown Manhattan building wearing dark clothes and sunglasses and carrying what appears to be a large firearm.
A motive has not been determined.
Caleb Clarke, a former classmate and high school football teammate said that Tamura “was the biggest goofball in the world, just a ton of energy, class clown.” The two played together in California until Tamura transferred from Santa Clarita to Grenada Hills in 2015, just before their senior year.
Clarke said that in recent years, he and Tamura kept up only through social media, where Tamura shared that he had been working at a casino in Las Vegas. But he doesn’t recall Tamura ever being a troublemaker in school. “You never would have thought violence was something you’d associate with him. You know, he could make a joke about people, but that’s just typical. Shane was a jokester. Everything he said was a joke. He had a ton of energy.”
He added that it seemed as if Tamura was destined for greatness as an athlete.“I feel like it was definitely on the table for him,” Clarke said. “I don’t think he walked around to be like, ‘Oh, I’ll have NFL games one day.’ I think it was more of everybody just telling him how great he was … how special he was.”
The building
Midtown Manhattan’s 345 Park Ave. is the headquarters of the investment firm Blackstone.
The building also hosts the headquarters of the NFL and a Bank of America branch, as well as offices belonging to KPMG.
Blackstone, Bank of America and the building’s owner, Rudin Management, did not immediately respond to requests for comment.
In a statement, KPMG said its thoughts were with victims and their families.
“Our hearts go out to the victims of this horrific act and their families,” it said. “We are incredibly grateful for the bravery of building security and law enforcement.”