Law enforcement officials investigate a contractor's SUV on the Baltimore-Washington Parkway after a man took a hammer to Jeep, which had speed cameras mounted on it. (Ann Heisenfelt/AP)

Maryland State Police closed down the Baltimore-Washington Parkway for more than three hours Wednesday as they searched for a man who was carrying a shotgun and hammer and smashed the windshield of a Jeep SUV that had speed cameras mounted on it.

Nobody was injured. As of Thursday morning, police were still searching for the man, who was described as wearing a plaid, possibly flannel, shirt on an 87-degree day.

A state contractor was inside the Jeep, which was parked on the side of the BW Parkway about 11:30 a.m near a construction zone at Route 195. The cameras were supposed to monitor speeding near the work area.

A man came out of a nearby strip of woods wielding a shotgun and a hammer. He began tapping on the rear of the Jeep with the shotgun, said Maryland State Police spokesman Greg Shipley. The worker became frightened and started blowing his horn.

“The suspect then came to the front of the Jeep and began yelling incoherently and smashing the windshield with the hammer,” Shipley said.

Law enforcement vehicles line the Baltimore-Washington Parkway in Linthicum, Md. while police search for an armed man who damaged a contractor’s SUV. (Ann Heisenfelt/AP)

The windshield shattered, Shipley said, and the worker got out of the car and crouched by the guardrail for cover. The man with the hammer and gun then left.

“The suspect disappeared into the wooded area,” Shipley said. “We’re still looking for him.”

Shipley said he did not know whether the man was angry about the speed camera or if he had another motivation.

Police described him as white, 60 to 65 years old, 5-foot-8 and 150 pounds, with gray hair and wearing a red and blue checked shirt and blue jeans.

Local officers on foot, canine units and helicopters assisted State Police in the search. The parkway reopened about 3 p.m.

State Police and the State Highway Administration announced last year that they were deploying speed cameras in the area. The posted speed through the work zone is 55 mph. Under state law, drivers exceeding the speed limit by 12 mph are fined. The fine is $40 for each violation.

The work zone is in place as the parkway is widened from Interstate 195 to I-695. The $12 million project is scheduled to be completed by spring 2012.