Family and friends of a missing north Minneapolis man searched along railroad tracks in Anoka on Tuesday afternoon, five days after his disappearance.

Authorities said Tuesday they have found no signs of foul play in the disappearance of Jelani Brinson, 24, but are considering that possibility.

"We are expanding beyond [just] the search for him," said Lt. Paul Sommer, of the Anoka County Sheriff's Office, which has joined the case. He said investigators are talking to friends and relatives of Brinson to seek possible reasons for his disappearance Friday night after he abruptly left a friend's house in the 600 block of Kennedy Street in Anoka.

Brinson's mother, Alyce Hamilton, said she and others returned Tuesday afternoon to Anoka to look for her son, who has a 9-month-old daughter. She said they were searching along the railroad tracks, starting near his friend's house, to retrace the scent trail followed by tracking dogs Sunday into neighboring Ramsey.

Searchers found Brinson's Adidas tennis shoes Sunday near fences on opposite sides of the railroad tracks not far from the Anoka home.

"The longer he's gone, the more we all are concerned," said Anoka Police Chief Phil Johanson. "We are working on it very hard with the Sheriff's Office."