A 32-year-old-Prince George's County woman was kidnaped at gunpoint by a man described as her former boyfriend who forced her car off the road early yesterday in Laurel, a county police spokesman said.

The woman, whom police would not identify, and her sister were driving in Laurel at 5:30 a.m. when Steven Thomas, 27, forced them to pull their car over, police said. Police have obtained a warrant to arrest Thomas on charges of kidnaping and assault to commit murder.

Police said Thomas displayed a handgun and fired one shot into the ground then put the gun to the kidnaped woman's head as he pulled her from her car, forced her into his vehicle and sped away. Police said the woman's sister followed Thomas' car in the victim's auto until he stopped at a sand and gravel pit where Thomas told the two women he was going to transfer to the victim's automobile.

Police said the victim's sister refused to give up the car, so Thomas placed the gun to the victim's head again and forced her back into his car, then sped away.

Thomas was driving a beige and green, 1969 Buick Skylark with Maryland State tags EXZ 388. County police asked anyone with information concerning the kidnaping should call: 336-8800.