The man from Florida held a shotgun to his chin for hours and was safely taken into custody, CBS2's Tony Aiello reported.
The 64-year-old suspect lifted up his coat and shirt to show he was not holding explosives then peacefully surrendered to police, ending a three-hour standoff right outside the entrance to one of New York's most sensitive locations.
"He does not have a criminal record or criminal history neither here in New York nor elsewhere around the country," said NYPD First Deputy Commissioner Ben Tucker.
NYC Parks worker Brian Osborn was across First Avenue at Ralph Bunche Park when it started just after 11 a.m.
"We didn't understand why everyone was running, and then we noticed all the police officers and all the commotion, and then when we looked to our right, I noticed the gentleman is holding a shotgun to his head. We said, 'Oh my god!' We panicked, we froze in the truck. We couldn't move," Osborn said.
Cops arrived almost immediately, according to Osborn. A tactical unit truck with a sniper behind a protective shield was on the scene.
Negotiators spent hours trying to convince the man to give up. He eventually removed notebooks from a backpack. Police, behind a blast shield, retrieved them.
The man surrendered when he saw police deliver the books to a U.N. official.
"They didn't have any specific meaning that was related to anything related to terrorism. But they were medical papers and some other documents," Tucker said.
The massive police response and street closures snarled traffic near 42nd and First.
"You can't go here and there because everything's blocked off. But thankfully no one was hurt," said Lynda Gregory, a Turtle Bay resident.
The NYPD Bomb Squad arrived as a precaution, but police said there was no indication the suspect had any type of explosive device.
Police said he drove from Florida to New York and checked into a hotel on 44th Street on Wednesday. The suspect's room and pickup were checked for danger and cleared.
Doctors were evaluating the man's mental condition. Charges against him were pending.
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