33-year-old Christopher Palumbo walked out at about 4 p.m. after being brought in by the NYS Office of Mental Health Police.
He left on foot heading in an unknown direction, police said.
Clarkstown Police set up a command post where they searched for the prisoner into the night.
On Monday evening Palumbo was spotted running across N. Main Street in New City, and was subdued by officers.
He was taken back to the Rockland Psychiatric Center.
Police said Palumbo was not believed to be armed.
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