A lone gunman with a history of mental illness drove cross-country to New York City from Las Vegas to carry out a shocking Monday evening rampage inside a Manhattan office tower, killing an NYPD officer and three others before turning the gun on himself. 

Security camera footage captured the 27-year-old gunman, identified in published reports as Shane Tamura, of Las Vegas, entering 345 Park Avenue — a prestigious, 44-story building in Midtown that houses companies like KPMG, Blackstone, Rudin Management, and the NFL as tenants — carrying a high-powered M4 assault rifle.

Once in the lobby, Tamura immediately opened fire, striking an NYPD officer.

The officer, identified as 36-year-old Didarul Islam, was a three-and-a-half-year veteran who was assigned to the 47th Precinct in the Bronx. He was working inside the lobby of 345 Park Avenue as part of the police department’s Paid Detail Unit on Monday evening. Mr. Islam, an immigrant from Bangladesh, was the father of two sons. His wife is pregnant with their third child, the police commissioner, Jessica Tisch, told reporters during a press conference Monday night. 

“He put himself in harm’s way. He made the ultimate sacrifice, shot in cold blood, wearing a uniform that stood for the promise that he made to this city. He died as he lived, a hero,” Ms. Tisch said.

The sight of a man carrying an assault rifle into a Midtown office building was terrifying and unusual. Seldom has the city experienced a mass shooting inside an office building — with an assault rifle, no less. 

“The horrific crime reminds us all how easy it is to gain access to a gun,” Mayor Adams said during a Monday evening press conference.

According to authorities, sometime before 6:28 p.m. Monday, Tamura double-parked his black BMW on Park Avenue between 51st and 52nd Streets and exited his car while carrying his assault rifle.

Tamura then entered the lobby of 345 Park Avenue, turned right, and immediately opened fire on Officer Islam, killing him. He proceeded to shoot a woman who was taking cover behind a pillar inside the lobby before spraying the lobby with gunfire. 

“He makes his way to the elevator bank, where he shoots a security guard who was taking cover behind the desk,” Ms. Tisch said. Tamura also shot another man inside the lobby during his rampage.

At the elevator bank, Tamura allowed a woman to exit an elevator and walk past him unharmed. Tamura took that elevator to the 33rd floor, where a real estate development firm that also manages the building, Rudin Management, has its offices. It’s not yet known if Tamura was specifically targeting Rudin, a century-old, family-owned New York City real estate giant. 

Upon exiting the elevator, Tamura continued to fire shots throughout the office as he walked the floor, striking and killing a woman.

The gunman walked down the office hallway before turning the rifle on himself and firing the weapon directly into his chest. He was pronounced dead at the scene.

Islam was brought to NewYork-Presbyterian, where he was pronounced dead. A wounded male civilian was also brought to NewYork-Presbyterian, where he was listed in critical but stable condition Monday evening.

Two other shooting victims, a man and a woman, were brought to Bellevue, where they were pronounced dead.

An image that the New York Post identified as that of Tamura’s lifeless body, splayed on the ground alongside an office cubicle, was circulating on X Monday evening. A motive for the shooting was not immediately clear. An image of the gunman’s assault rifle, partially covered in blood, was also circulating on X Monday.

Police searching Tamura’s BMW recovered a rifle case with rounds, a loaded revolver, ammunition magazines, and medication prescribed to him. A bomb squad found no evidence of explosives inside the car. 

Ms. Tisch said Tamura left Las Vegas on July 26 and drove across the country through Iowa and Nebraska the following day, driving through New Jersey late Monday afternoon before arriving at 345 Park Avenue.

Las Vegas law enforcement officials confirmed that Tamura had a documented history of mental health problems. However, Tamura’s motives and why he specifically targeted 345 Park Avenue were still unclear late Monday evening.

The shooting prompted a widespread police response in Midtown Manhattan, where footage showed police racing to the scene while office employees dressed in suits were seen being raced out of the building.

Images on X showed office employees using office furniture to barricade themselves from the shooter. 

Outside the office building, the NYPD were seen arresting two other people, including a man wearing a “Palestine” sports jersey who allegedly yelled “Free Palestine” during the police response. The protesters are not believed to have any connection to the gunman. An NYPD spokesman could not confirm why the two were arrested or whether they were facing charges.

A New York mayoral candidate and Democratic Socialist, Zohran Mamdani, who has repeatedly called to “defund the police” in the past, said he was “grateful for all of our first responders on the ground.”

“I’m heartbroken to learn of the horrific shooting in Midtown and I am holding the victims, their families, and the NYPD officer in critical condition in my thoughts,” Mr. Mamdani wrote on X. 

At Monday’s press conference, Mr. Adams pledged to “continue to do what we do as a city, and that’s fight to protect innocent New Yorkers.”