A gunman armed with an assault-style rifle killed four people inside a Manhattan skyscraper on Monday before turning the gun on himself, according to New York City officials.

Among the victims was 36-year-old NYPD officer Didarul Islam, an immigrant from Bangladesh and a father of two, who was serving as part of a security detail at the time of the shooting. Mayor Eric Adams hailed him as a “true blue” hero.

The shooter, identified as 27-year-old Shane Tamura from Las Vegas, reportedly had a history of mental illness and had travelled cross-country to New York in the days leading up to the attack.

Authorities have not yet established a motive for the shooting, which began in the lobby of the Park Avenue tower and moved to the 33rd floor before the gunman took his own life.

In addition to the four fatalities, a male victim was critically wounded and is currently “fighting for his life” in a nearby hospital.

Police Commissioner Jessica Tisch confirmed that the gunman acted alone and noted that preliminary background checks revealed no significant criminal history.

The incident occurred during the evening rush hour in a building that houses the headquarters of the NFL and several major financial firms, including Blackstone and KPMG.

A significant police presence was deployed to the area as investigators began their work.

Witnesses described scenes of chaos, with one bystander noting, “I just saw a lot of commotion and cops and people screaming.” The FBI has also sent agents to assist at the scene.

Despite the traumatic event, some nearby workers, like Kyle Marshall, expressed confidence in the police response and a commitment to feeling safe in Manhattan.