UPDATE: He's been found and is safe, police say.
Boston Police report they are looking for Jeffrey Cooper, last seen on Border Street on Friday.
Cooper, who has been going on walkabouts since he was a young teen, is 23, about 6' tall and has a slim build. He was last seen wearing a Celtics baseball cap, prescription eyeglasses with a gray, white and black shirt, blue jeans and a gray sneakers and carrying a a gray backpack. Jeffery is autistic and is not verbally responsive.
If you see him, call 911 or detectives at (617) 343-4234.