Michael Trissler was last seen at 760 20th Ave. N.W. around 11:30 p.m. Saturday, detectives said.
Detectives said family members believe Trissler may harm himself.
Trissler is described as white, 5 feet 10 inches tall and 160 pounds with brown hair and brown eyes. He was last seen wearing black shorts and a black t-shirt with the words "Big Rob" along with a red backpack.
Anyone with information is asked to call the Collier County Sheriff’s Office at 239.252.9300.
