A potential candidate in the recall election against state Sen. Russell Pearce was struck in the groin with a padlock thrown from a pickup while he was out jogging, Mesa police said.

Authorities are investigating whether the assault was a random act or politically motivated.

According to a police report on the incident, Jerry Lewis, 54, was jogging with a friend along Brown Road in north central Mesa about 6:30 a.m. and doubled over in pain when he was struck but did not require medical attention.

A white Chevrolet pickup with chrome wheels, pulling a black trailer, sped away. The suspect was described as a White male, 35-40 years old, wearing a black long sleeve shirt with short brown hair.

Sgt. Ed Wessing, a Mesa police spokesman, said police don't have enough information to determine the motivation for the attack.

"Based on the little information we have, I don't know if it's something that was planned," he said.

Wessing said it is unusual for someone jogging or riding a bicycle to be attacked in such a manner early in the morning. He said people sometimes report having objects thrown at them from time to time.

"No, that's not a frequent occurrence," he said.

A friend of Lewis, Daniel Jacobson, found a green and black Master Lock lying near Jacobson shortly after the incident and turned it over to police.

Wessing said police will analyze the lock forensically to see if they can identify any fingerprints or DNA that might help identify Lewis' attacker.

He said neither Lewis nor Jacobson reported a license plate number on the truck and attempts to locate the pickup were unsuccessful.

Lewis is expected to announce Wednesday whether he will run for Pearce's seat in the unprecedented Nov. 8 recall election. Pearce is believed to be the first legislator to face a recall election in Arizona history. Pearce is known nationally for spearheading SB 1070, a controversial anti illegal immigration law, and other immigration legislation.