A $13,500 reward was posted this afternoon for information on a suspect who shot a Chester County police officer in the hand Sunday.

The man, deemed by police to be a serious threat to the public, is described as stocky, white, clean-shaven, in his mid to late 20s and about 6 feet tall, with short, dark hair. He fled with a woman in a late-model, dark-colored Honda sedan after he shot a 12-year veteran of the Westtown-East Goshen regional police department.

At a news conference, Police Chief John M. Dumond said Cpl. Tim Hubbard stopped about 11:30 p.m. when he saw a man and woman arguing on East Strasburg Road near Dutton Mill Road, a remote area near the Ashbridge Preserve in East Goshen Township.

When Hubbard approached, the man fired what appeared to be a semiautomatic handgun at close range, Dumond said. Hubbard had raised his arm and was hit in the left hand; he returned fire, but it was not known if he hit the gunman, Dumond said.

Dumond said Hubbard was recovering after his release from the hospital. He said police remain concerned about the woman's well-being.

"You are not safe if you were with this man that evening," Chester County District Attorney Joseph W. Carroll said.

Authorities said clothing left at the scene might help identify the couple: a dark blue Wilmington Blue Rocks baseball cap that says "Christiana Care Health System" on the back, and a medium-sized, short-sleeve, blue Villanova basketball shirt.

Anyone with information is asked to call the Citizens' Crime Commission at 215-546-8477, or the Chester County Police Radio at 610-692-5100.

Contact staff writer Kathleen Brady Shea at 610-696-3815 or kbrady@phillynews.com.