A gunman wearing a blue T-shirt over his head robbed a Hennessey convenience store of $400 shortly after 11 p.m. Sunday, according to a Hennessey Police Department report.

The robber brandished a black handgun and ordered two male clerks at the Sinclair Main Street Truck Stop at the corner of U.S. 81 and S.H. 51 into a public bathroom after he made them empty each of their cash registers.

“Then he put a stool in front of the door, and as soon as the clerks heard the ding of the guy leaving the store, they just pushed open the door,” Hennessey Assistant Police Chief Ed Cangiano told the Times and Free Press.

Exterior surveillance cameras showed the man run across the street west after going through the Dollar General Store parking lot north of the truck stop, according to a written police statement.

Cangiano said the cameras also showed the headlights of a waiting vehicle that headed north. The vehicle was not identifiable in the video.

The clerks were not reported injured and no customers were inside the store at the time of the robbery.

Inside surveillance cameras showed that the robber was a white male approximately 6 feet tall, medium build with gray hair.

He wore a black T-shirt, possibly an OSU shirt, with the sleeves cut off, khaki colored pants, black tennis shoes and was armed with a black pistol.

A blue T-shirt was pulled over his head.

According to Kingfisher County Sheriff’s Office dispatch call logs, one of the clerks reported the man was shaking as he made his demands.

Sheriff’s deputies Rodney Walker, Kendon Lott and Todd Davis also responded to the scene and checked area businesses, farm houses, lease roads and county roads for a fleeing vehicle or other signs of suspicious activity, according to the sheriff’s office dispatch log.

Garfield County law enforcement also were notified, according to the log.

Anyone with information about the robber’s identity or whereabouts is asked to contact the Hennessey Police Department at (405) 853-4444 or call 911.

Hennessey correspondent Barb Walter and Senior Editor Christine Reid contributed to this story.