VISTA–An adult male caught Wednesday afternoon fanning flames in the San Luis Rey riverbed in Oceanside pleaded not guilty to arson charge in Vista court on Friday.

Alberto Serrato, 57, was arrested by police after he was spotted in the riverbed during the fire that burned about 105 acres, Oceanside police says.

The judge set Serrato’s bail to $250,000. He faces seven years in prison if convicted of felony arson.