Lewis McDaniel was lying in bed, watching a late night TV show early yesterday, when his 19-year-old daughter, Titia, burst into the room shouting: "Daddy, I hear somebody outside."

McDaniel got his .22-caliber handgun, looked out the window and fired two shots out the back door of their Fairfax County home. The prowler, a naked man, ran away.

McDaniel, 66, a retired school building supervisor who had suffered a heart attack in March, went into the living room and told his wife to "Bring me my nitroglycerin." She had just got the top off the bottle when she heard him fall on the floor.

Rescue personnel took him to Commonwealth Hospital in Fairfax City where he was pronounced dead.

"He wasn't supposed to have any excitement," said Rose McDaniel, referring to her husband's heart condition. "It upset him so," she said of the discovery of the prowler outside their home in Centreville.

Police, who searched for the suspect unsuccessfully by helicopter, said they received three complaints of prowlers in the Lewis Park community earlier, which matched the general description of the prowler at the McDaniel house on Braddock Road.

Mrs. McDaniel said it wasn't the first time that someone had tried to get into the house. The mother of four said that late last week a man "busted" through the screen of the front door and was found by her husband bent over in the living room. She said her husband, who worked for the Fairfax school system, yelled at the intruder and he dashed away.

The man left a picture of naked women and a chair outside their bedroom window. Police were not called, she said. "I guess we should have."

Fairfax police said they are investigating a burglary-assault Monday in the Oakton area to see if it is connected with yesterday's incident.

In the Oakton incident a 25-year-old woman was awakened in her bed by a naked man. She screamed and struggled with the man, who had entered the house on Blake Lane by removing a screen door, and frightened off the man, police said.

The woman did not require medical treatment, police said.