GRANTSBURG, Wis. (AP) -- The sheriff of Burnett County in northwestern Wisconsin says the search for an autistic man missing since Sunday night has come up empty so far, but it will continue through the weekend.

Twenty-five-year-old Keith Kennedy from Shoreview, Minnesota, wandered away from a camp for developmentally disabled adults in the Grantsburg area and hasn't been seen since.

He only can speak four words and relies on anti-rejection drugs after having a kidney transplant in 1995. If he misses too many doses, his kidneys could start to shut down.

Sheriff Dean Roland says hundreds of searchers have covered 14 square miles and have found no sign of him.

The sheriff is now seeking the public's help in asking whether anyone may have given Kennedy a ride. He says tracking dogs picked up a brief scent of Kennedy but then it just disappeared.

But he also says Kennedy is in good physical condition and could survive alone in the wild.

The search resumes today.