Madison police are looking for a man suspected of beating an Uber driver unconscious near the University of Wisconsin campus.

Police say the 22-year-old driver picked up a man and two women last Saturday evening near the end of the Wisconsin-Iowa football game.

The driver says the man got into the back seat of the van directly behind him and punched him in the side of the neck. The suspect then wrapped his arm around the driver's neck, causing him to black out.

Police say the van accelerated, jumped a curb and hit a traffic sign. The three people then walked away. The victim told police the clients canceled the ride, eliminating his record of the transaction.

Investigators are working with Uber to find out who ordered the ride.