Port Authority officers assigned to the World Trade Center handed him a pen -- on which the man wrote an address that ended up reuniting him with his family.
Loved ones and others distributed fliers and police had issued alerts in the search for 21-year-old Tanvir Hossain.
Hossain, who's non-verbal and has schizophrenia, was last seen on Sunday.
The officers who found him flashed his photo to the NYPD's 52nd Precinct.
Officers there took it to Hossain's parents, who identified him.
The family was reunited soon after.
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