Fire and police officials said the bodies of the girls, ages 5, 7, 9 and 17, were in an advanced state of decomposition and their deaths were being investigated as homicides, The Washington Post reported. The causes of death had not been determined.

The marshals found the bodies in the two-story gray brick row house after being let in by a woman who answered the door, the Post said. A law enforcement source said the woman, who was being interviewed at police headquarters but had not been charged with a crime, was the girls' mother.

Police Chief Cathy L. Lanier said it didn't appear the house had been entered forcibly. "I don't want the impression that someone kicked in the door and carried out this crime," she said.