NEW YORK - The gunman who killed four people at a Manhattan office building was trying to target the headquarters of the National Football League (NFL) but took the wrong elevator, the Associated Press reported Tuesday, citing New York City Mayor Eric Adams.

Investigators believe Shane Tamura was trying to get to the NFL offices after shooting several people Monday in the building's lobby, but accidentally entered the wrong set of elevator banks, Adams said on Tuesday.

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US President Donald Trump said on his Truth Social platform that he had been briefed on the tragic shooting. "I trust our Law Enforcement Agencies to get to the bottom of why this crazed lunatic committed such a senseless act of violence."

"My heart is with the families of the four people who were killed, including the NYPD Officer, who made the ultimate sacrifice," Trump said.

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The 27-year-old Tamura opened fire around 6 pm local time (2200 GMT) and died from "an apparently self-inflicted injury," CNN reported. The information was later confirmed by Adams.

The gunman reportedly came from Las Vegas. Authorities found a vehicle with Nevada plates registered to Tamura at the scene with a rifle case inside, according to the New York Post.