The New York City police officer who was killed when a gunman opened fire in a midtown Manhattan building on Monday evening was a dedicated father and civil servant who was working a second job as a security guard, according to officials.

Didarul Islam, a 36-year-old immigrant from Bangladesh, was the first person to be shot in the attack at 345 Park Ave. that left four others dead, including the gunman, authorities said.

Islam had been with the police department for about four years and leaves behind two young sons and a wife who is pregnant, according to the New York Police Department.

“He was doing the job that we asked him to do,” NYPD Commissioner Jessica Tisch said at a news 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.”

She added that Islam was working off-duty through a police department program that allows companies to hire officers in uniform to provide extra security.

Those who knew Islam said he “believed in living out the life of a godly person,” said New York City Mayor Eric ams, who told reporters at the news conference that he had met with Islam’s family earlier in the night.

“I told them that he was a hero, and we admire him for putting his life on the line,” said ams, who is a former police officer. “He embodies what this city is all about. He’s a true-blue New Yorker, not only in a uniform he wore, but in his spirit and energy of loving this city.”

Officials said the motive for the attack was still under investigation. Shane Devon Tamura, a 27-year-old from Las Vegas with a “documented mental health history,” has been identified by police as the gunman. Authorities say he recently drove cross-country to New York, storming into the office tower and spraying the lobby with gunfire before taking the elevator to the 33rd floor to fire more shots and then turning his weapon upon himself.

Two officials familiar with the matter told NBC News that the shooter, who played football in high school, left a note at the scene that said he wanted his brain studied for chronic traumatic encephalopathy, or CTE — a neurodegenerative disorder associated with head injuries that has been diagnosed in hundreds of NFL players after their deaths and that can cause changes in behavior and cognition.

The corporate building where the shooting took place houses the headquarters of the NFL, though it was not immediately clear whether the NFL was the intended target. One NFL employee was seriously hurt in the attack, according to the league’s commissioner, Roger Goodell.

In addition to Islam, the dead include another security officer and an executive at Blackstone.

Islam had been stationed in the lobby of the building close to where the gunman entered, officials said. The officer’s family remembered him as a loving father who was devoted to his religion.

“When he had time, and especially his off-days, he went to the mosque with his two kids,” Muhammad Mainul Islam, who identified himself as Islam’s cousin, told NBC New York on Tuesday.

Islam had been assigned to the 47th Precinct in the Bronx. The head of New York City’s police officers’ union said relatives described him as proud to put on the “uniform and shield of a New York City police officer.”

“He went out every single day to provide for his family, whether it was overtime or whatever he had to do,” said Patrick Hendry, the president of the Police Benevolent Association.

In a Tuesday morning interview on MSNBC’s “Morning Joe,” ams said Islam was the first Bangladeshi-born NYPD officer to be killed in the line of duty. He and New York Gov. Kathy Hochul on Tuesday ordered flags on government buildings to be flown at half-staff in honor of Islam and the other shooting victims.

In a post on X, the NYPD shared a video of police officers saluting during a dignified transfer ceremony overnight for Islam, his body draped in a flag.

“A husband, a father, a son. He leaves behind a city in grief,” the post read.

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