The first woman found dead yesterday in a house in Northwest Washington was a cancer patient, and police believed initially that her death was of natural causes. But when a second woman was found dead in the same house, amid signs that she had been attacked, police called the deaths a possible double homicide.

In a twist that underscored the grisly nature of yesterday's events on Hamilton Street NW, the body of the first woman, identified as Dorothy Redd, 65, already had been released to a funeral home when the investigation suddenly changed course and authorities took custody of it.

Police said Redd lived in the house in the 600 block of Hamilton Street. The second woman was also believed to live there, possibly in quarters separate from Redd's. She was not identified immediately.

Police said autopsies would be conducted on both bodies. The said they had leads in the case but had not identified a suspect.

The discoveries in the house just north of the Petworth neighborhood began about 10 a.m., just after a relative of Redd's went there, police and neighbors said. The relative was concerned about Redd's welfare, authorities said. The reason for the concern was not immediately known, but police said Redd's cancer was described as terminal.

The relative opened the front door and found Redd's body on the first floor, police said.

There was "no indication" that Redd's death had been anything but natural, said Lt. Alvin Brown, commander of the violent crime unit in the 4th Police District. Police said her doctor was called, and it was decided to treat the death as of natural causes. A funeral home was notified, and Redd's body was taken from the house and placed in a vehicle belonging to the home.

Before that vehicle left with Redd's body, however, the second body was found in the basement. Although the nature of that woman's injury was unclear, one police official said it might have been inflicted by a blunt object.

That discovery changed the course of the investigation.

Monica Gant, a neighbor on Hamilton Street, said that as soon as she learned of the second body, she ran to the funeral home's vehicle.

"Stop," she recalled telling the driver. "This," she said, referring to the house, "is now a crime scene."

The body was later transferred to the custody of the D.C. medical examiner.

Gant described Redd as a generous woman who was quick to laugh and took a lively interest in the upbringing of neighborhood children.

She was "a really sweet person," said another neighbor, Renee Jennings, 19. "She looked out for our neighborhood."

The death of Redd under circumstances that have not been explained follows the unexplained deaths of two other older women in their Northwest homes in recent weeks. Police said they have no evidence of a connection among them.

Staff writer Martin Weil contributed to this report.