Officials say arson was the cause of a fire on a central Minnesota bridge Saturday. A bicyclist reported the fire on Wobegon Trail bridge in Albany Township. The trail was temporarily closed by investigators, but is now reopen and the DNR has determined the bridge is again safe for travel. The Minnesota Arson Reward Project is offering a $5000 reward for tips leading to a conviction in the case. Anyone with information is urged to call the Arson Hot-Line at 800-723-2020.