The wife of a man suspected of a triple murder in Lorton has been charged with a carjacking in Alexandria, police said yesterday.

Police have been searching for Michelle Yi Gardner, 19, who vanished shortly after her husband, Keith J. Gardner, 39, was arrested June 1 in Florida.

Keith Gardner was arrested on probation violation charges and is being held at the Fairfax County jail. He has not been charged in the stabbing deaths of his mother, father and grandfather, whose bodies were discovered May 11 in a fallout shelter behind the home where he had been living.

Police believe the April 21 carjacking occurred before the slayings of Keith Gardner's parents, Jimmy and Jannis Gardner, and his grandfather, Elmer Gardner. The Gardners were likely killed within two weeks of the discovery of the bodies, police said.

Video cameras at the Exxon station at 4550 Kenmore Ave. in Alexandria and at nearby businesses captured a man and a woman loitering around the station on the afternoon of April 21. Alexandria police spokeswoman Amy Bertsch said the woman approached a 37-year-old man who was pumping his own gas, asked for a ride in his 1998 green Honda Civic, then signaled for a man to join her.

"We believe that man is Keith Gardner," Bertsch said, though he has not been charged in the carjacking.

When the man pumping his gas refused to give either person a ride, the male suspect climbed into the driver's seat. When the car's owner tried to reach in and retrieve his car keys, the male suspect bit him, Bertsch said.

The female suspect then yanked the driver away from the car by his hair, and the male suspect pulled the car away from the pumps, slamming his open door against a concrete post.

On June 25, Fairfax police found the car in the Fort Belvoir area. Three days later, Alexandria police obtained a warrant for Michelle Gardner on a charge of carjacking, Bertsch said.

Fairfax police declared Keith Gardner a murder suspect within days of the discovery of the three bodies, and before he fled to Florida he had been spotted numerous times in downtown Washington, possibly to further his addiction to Dilaudid, a synthetic narcotic. Detectives said Michelle Gardner also may be staying in the District, after vanishing from her family's Reston home.

Michelle Gardner is described as 5 feet 1 inch tall, weighing about 90 pounds. Alexandria police are offering up to a $1,000 reward for information leading to her arrest.