Word on NPR had something to do with a warm body being spotted by police scanning the area with thermal equipment, likely from the helicopter that had been seen earlier.

If it were not for the thermal, they likely would not have gotten him. He would sleep off the day, and late at night sneak out of the boat and try to escape. Maybe even sleep off two days hiding in the boat, but not after being spotted on thermal.

Makes hiding in a vehicle a whole new ball game.