An off-duty police officer and a civilian were shot outside an office building on Park Avenue on Monday, police sources told ABC News.
The suspect then fled into the building, located at 345 Park Ave., sources said. After apparently barricading himself on the 33rd floor, he was found dead from what is believed to be a self-inflicted gunshot wound, sources said.
The conditions of the victims were not immediately known. The officer was working security at the building, sources said.

A police officer and a civilian were shot outside an office building on Park Avenue on Monday, police sources told ABC News.
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Surveillance footage captured the suspect outside the building armed with a long gun, according to sources.
The motive is currently under investigation, FBI Deputy Director Dan Bongino said.
There is a lockdown at the office building, which contains the headquarters for the investment company Blackstone and the National Football League, sources said. It is unclear if those companies, or any company in the building, were tied to the shooting.

A police officer and a civilian were shot in Midtown Manhattan on Monday by a suspect who fled into an office building, police sources told ABC News.
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Some of the employees inside 345 Park Ave. have been advised that the threat “has been resolved” but are being asked to continue sheltering in place and only leave the building with a police escort, according to a message sent to employees.
New York City Mayor Eric Adams earlier warned residents to avoid the area amid the “active shooter investigation.”
The New York City Police Department also urged people to avoid the vicinity of East 52nd Street between Park Avenue and Lexington Avenue due to police activity.
“Expect emergency vehicles & delays in the surrounding area,” the NYPD said on social media.
FBI New York Field Office management personnel and agents responded “to provide support at the active crime scene in Manhattan,” Bongino said on X.
New York Gov. Kathy Hochul said she has been briefed on the situation.
This is a developing story. Please check back for updates.