What happened?, Who is the gunman?, Who are the victims and the injured?, What happens next in the investigation?, What have witnesses said?

Suspected gunman Shane Tamura is accused of opening fire in a Midtown Manhattan office building in New York City on Monday evening and killing four people, including a New York police officer, before turning the gun on himself.

“I want to extend my profound sympathies to all of the victims and their families, and to the brave NYPD cops who today lost a brother,” NYPD Commissioner Jessica Tisch said at a press conference on Monday evening.

“There are still many questions that we have to answer, and we will answer them. For now, our city is in mourning for the innocent lives lost. May their memories be a blessing.”

What happened?

At 6:28 p.m., police began getting calls from the skyscraper at 345 Park Avenue, home to the offices of the NFL and Blackstone, about an active shooter.

Security cameras captured Tamura, 27, double-parking a black BMW on the street outside the office tower and entering the building holding what was later determined to be an M4 assault rifle, Tisch said.

The 27-year-old, who had a Las Vegas, Nevada, address, proceeded to “immediately open fire” on the ground floor of the building, Tisch said at the press conference, striking NYPD officer Didarul Islam, 36, who later died of his injuries.

Police said Tamura continued firing, shooting at a security guard taking cover behind a desk and another man. The gunman is then accused of taking an elevator to the building’s 33rd floor, which houses the offices of Rudin Management.

Police say gunman Shane Tamura, who died of a self-inflicted gunshot wound in the shooting, used an M4 rifle and had a revolver and ammunition in his car (NYPD)

Inside the office, police say Tamura continued firing, striking and killing another person, and then shooting himself in the chest.

Tamura is believed to have acted alone, and there is no longer a threat to the public, according to police.

Who is the gunman?

Police believe Tamura, a 27-year-old Las Vegas man, acted alone in the shooting.

The suspect was a native of Hawaii and was raised in Santa Clarita, California, where he was a standout running back at Granada Hills Charter High School.

In addition to holding a concealed carry license for a handgun, he also had an expired private investigator's license.

“He has a documented mental health history,” Tisch said Monday. “His motives are still under investigation. We are working to understand why he targeted this particular location.”

Tamura did not have a significant criminal record.

Police believe Tamura, a 27-year-old Las Vegas man, acted alone in the shooting (Supplied)

In a suicide note discovered by authorities, Tamura wrote that he was suffering from chronic traumatic encephalopathy, a brain disease that has been linked to head trauma regularly endured by football players.

“Terry Long football gave me CTE and it caused me to drink a gallon of antifreeze. Study my brain please I’m sorry Rick I’m sorry for everything... You can’t go against the NFL, they’ll squash you,” the note reportedly read in parts.

In 2005, former Pittsburgh Steelers offensive lineman Terry Long took his own life after drinking a gallon of antifreeze. He was later diagnosed to be suffering from CTE.

Tamura appears to have driven across the country through Colorado, Nebraska, and Iowa in the days before the shooting, police said.

His car was then spotted in Columbia, New Jersey, just after 4 p.m. the evening of the shooting.

Tamura appeared to be wearing dark sunglasses and a dark-colored jacket and carrying a large rifle as he approached the office tower, according to security video images.vada.

The FBI said Friday during the press conference that its systems did not contain additional prior information about the 27-year-old.

Who are the victims and the injured?

Tamura is accused of shooting dead at least four people, one of whom was the NYPD officer Islam.

The three others shot and killed are yet to be formally identified.

Islam served in the NYPD’s 47th Precinct in the Bronx and had been with the force for three-and-a-half years, officials said.

The Bangladeshi immigrant was a father of two young boys, and his wife is pregnant with the couple’s third child.

The NYPD said on X late Monday, “Police Officer Didarul Islam represented the very best of our department. He was protecting New Yorkers from danger when his life was tragically cut short today. We join in prayer during this time of incomprehensible pain. We will forever honor his legacy.”

NYPD Officer Didarul Islam was killed in the shooting Monday (NYPD)

The gunman killed four people inside the building before killing himself, police say (AFP/Getty)

“He loved this city and everyone we spoke with stated he was a person of faith and a person that believed in God and believed in living out the life of a godly person,” New York City Mayor Eric Adams said at the press conference on Friday. “He embodies what this city is all about. He is a true blue hero not only in the uniform he wore, but in his spirit and energy of loving this city.”

Another man was seriously wounded in the shooting, and four others were treated for “minor” injuries, Tisch said.

Police are still investigating what motivated the shooting at Manhattan skyscraper, and said suspected gunman Shane Tamura did not appear in the FBI’s records prior to the incident (Reuters)

What happens next in the investigation?

The NYPD is leading the investigation into the shooting.

Federal agencies, including the FBI and the Bureau of Alcohol, Tobacco, Firearms, and Explosives, are assisting on the case.

Police say they found a rifle case, rounds of ammunition, a revolver, and medication bearing Tamura’s name inside the BMW left outside the office building before the shooting.

Police officers search the building at 345 Park Avenue to determine what motivated the deadly shooting (AP)

After the search and evacuation of 345 Park Avenue, police said they were conducting a secondary sweep of the building.

Officers are still working to determine a motive.

What have witnesses said?

A witness to the shooting, Jessica Chen, told ABC News she was on the second floor with about 150 people when they heard “multiple shots go off in quick succession from the first floor.”

She ran into a conference room with others, and they barricaded the door.

“A lot of us were young, a lot of us went through training in elementary school of what to do in an active shooter situation. We were all, unfortunately, prepared,” Chen said.

Bystanders described hearing a wave of gunshots and barricading themselves inside high-rise officers during incident (AP)

Chen said they were in constant communication with police during the shooting.

While sheltering inside the conference room, Chen texted her parents that she loved them.

“We were honestly really, really scared,” Chen said. “All of us were frozen. All of us were shocked.”

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