Here are some things to know:
What happened?
A man exited a double parked BMW with an M4 rifle and then walked toward the skyscraper that is home to the headquarters of both the NFL and Blackstone, one of the world's largest investment firms, as well as other tenants on Monday evening, according to surveillance video.
He quickly opened fire on the NYPD officer as he entered the building before shooting a woman who tried to take cover, police Commissioner Jessica Tisch said at a news conference. He then started “spraying” the lobby with gunfire.
The gunman went to the elevator bank and shot a security guard who was taking cover behind a security desk and also another man in the lobby, Tisch said.
The gunman took the elevator to the 33rd floor to a real estate management company and one person was shot and killed on that floor. He then walked down a hallway and shot himself, the commissioner said.
What do we know about the gunman?
Police identified Shane Tamura of Las Vegas as the gunman. Tamura had a “documented mental health history,” Tisch said.
New York City Mayor Eric Adams said Tuesday that Tamura was trying to target the headquarters of the National Football League but took the wrong elevator. Investigators believe he was trying to get to the NFL offices but accidentally entered the wrong set of elevator banks, Adams said.
Police said a note found on Tamura's body suggested he had a grievance against the NFL over an unsubstantiated claim that he suffered from chronic traumatic encephalopathy. He had played football in high school in California nearly two decades ago.
The note, which referenced the NFL, claimed Tamura had been suffering from CTE and said his brain should be studied after he died, two people familiar with the matter told The Associated Press. The degenerative brain disease has been linked to concussions and other repeated head trauma common in contact sports like football.
A motive has not been determined but, based on the note, investigators were looking into whether he might’ve targeted the building because it is home to the NFL’s headquarters.
One challenge for the investigation is that Tamura arrived in New York shortly before the shooting, leaving few clues in the area, Adams said.
Tamura's vehicle had traveled across the U.S. through Colorado on July 26 and then Nebraska and Iowa on July 27. It arrived in Columbia, New Jersey, as recently as Monday afternoon, before making it to New York City, Tisch said.
Officers found a rifle case, a revolver, magazines and ammunition in his car, she said.
No one answered the door at the address listed for Tamura in Las Vegas.
Who were the victims?
Didarul Islam, 36, had served as a police officer in New York City for 3 1/2 years. He was an immigrant from Bangladesh.
Islam was married and had two young boys, Tisch said. His wife is pregnant with their third child.
His body was draped in the New York Police Department flag as it was moved from the hospital to an ambulance, with fellow officers standing at attention.
In a post on social media, Adams said he ordered all flags on city buildings to be lowered to half-staff until further notice to honor the fallen officer and the other shooting victims.
Blackstone confirmed one of its employees, Wesley LePatner, was among those killed.
“Words cannot express the devastation we feel,” the firm said in a statement. “Wesley was a beloved member of the Blackstone family and will be sorely missed. She was brilliant, passionate, warm, generous, and deeply respected within our firm and beyond.”
A Yale graduate, LePatner was a real estate executive at Blackstone, according to the firm’s website, and spent more than a decade at Goldman Sachs before joining the firm in 2014.
The names of the other victims have not yet been released.
NFL Commissioner Roger Goodell said in a memo to staff that a league employee was seriously injured in the attack and was hospitalized in stable condition. He said that “all of our employees are otherwise safe and accounted for.”
Where did the shooting happen?
The shooting took place in a busy area of midtown at 345 Park Avenue, a commercial office building on one the nation's most recognized streets near Grand Central Terminal, Rockefeller Center and St. Patrick's Cathedral. It's also less than a 15-minute walk from where UnitedHealthcare CEO Brian Thompson was shot and killed last December by a man who prosecutors say was angry over corporate greed, and Monday's attack could bring further attention to security in the business world.
The building houses offices for companies including the NFL and real estate company Rudin, as well as finance companies KPMG and Blackstone. It also includes the consulate general of Ireland.