Fairfax County fire officials yesterday sifted through the debris of a Tuesday night fire that killed a man and his 3-year-old daughter and injured his wife and 12-year-old step-daughter, but were still unable to determine the cause of the fire.

Fire Department spokesman Lt. Leonard D. Jackson said officials were baffled by the fire that rapidly engulfed the brick split-level home at 7519 Hamlet St. in North Springfield.

Harold T. Colgan, 40, who worked in the meat department at a Giant supermarket, was killed as the attempted to rescure his 3-year-old daughter Brandy, Jackson said. The bodies of Colgan and his daughter were found in a second floor bedroom, huddled together, he said.

Jackson said Colgan saved his wife, Georgianna, 30, by forcing her to jump from a second floor window in the front of the house. Colgan also threw his stepdaughter, Rhonda Barkley, through the front second floor window after the child balked when he told her to jump.

His son Richard, 10, and a stepson, Randy Barkley, 11, managed to escape through a basement door that led to the basement bedroom where they were sleeping. They were awakened by the shouts of a neighbor, Don Jaget.

According to Jackson, the family went to bed around 10:15 p.m. after watching television.

Shortly before 11 p.m., Jaget, and his wife Patricia, who live next door at 7517 Hamlet St., were preparing to go to bed when they saw the Colgan house in flames.

According to neighbors, the Colgans did not have a smoke detector.

Rhonda Barkley was listed in fair condition yesterday at Fairfax Hospital where she was being treated for burns to her arms and legs and abrasions to her back. Mrs. Colgan was treated at the hospital for minor burns to the shoulers and later released.

Five firemen received minor injuries in the blaze, which was reported at 10:54 p.m. In all, 35 firemen fought the fire, which took 15 minutes to bring under control. Officials estimated $90,000 in damages to the house.