WASHINGTON - U.S. Marshals delivering an eviction notice Wednesday found the decomposing bodies of four youths, ranging in age from 5 to 18, inside a home in one of this city's poorest areas, authorities said.

A woman who answered the door at the small, two-story brick apartment building where the bodies were found was taken into police custody for questioning, authorities said.

"She was apparently calm throughout," U.S. Marshals Service spokesman Cole Barnhart said.

Authorities were investigating the causes of death. District of Columbia Police Chief Cathy Lanier said it was unclear how long the youths had been dead, but she added, "I'd say more than several days."

The bodies were found upstairs in the southeast Washington apartment, part of a block of virtually identical apartment houses.

Larry Jones, who lives next door, said a woman and two or three children live at the home but that he had not seen them since the summer. He said the children appeared healthy at the time.

Jones added that in recent months he has noticed a "strange odor" coming through his vent.

"We thought it was probably dead mice in the vent or something," he said, adding that he had talked to the landlord about it.

Investigators were trying to determine if the woman at the home was related to the four, Assistant Police Chief Diane Groomes said. The woman's name and those of the dead youths have not been released.

D.C. Council member Marion Barry, who represents the neighborhood where the bodies were found, questioned why no one had reported the four missing.

"Somebody should have known that some people were not in school," said Barry, the former mayor.

D.C. schools spokeswoman Mafara Hobson said none of the children was currently enrolled in the school system. One had attended Stuart-Hobson Elementary School but withdrew in 2006 as a fifth-grader, she said.