The bodies of a man who appeared to be in his thirties, a woman in her twenties or late teens and a Doberman pinscher dog were found yesterday in a split-level house in Temple Hills where the grass on the unmowed lawn had grown to a foot in height.

Prince George's County police said the dog apparently had died of starvation in the house at 5319 Old Branch Ave., but that they did not know what had caused the deaths of the man and woman, whose bodies were badly decomposed.

County police spokesman Bruce Gentile said the man was found in the basement and the woman in a bedroom. Both probably had been dead for seven to 10 days, he said. Neither was identified and police said they were not certain if the two lived in the house.

The bodies were fully clothed and showed no sign of foul play, Gentile said, and there was no evidence of forced entry into the house or of any ransacking of its contents.

Neighbors said they had not seen the occupants of the house for about a month. One neighbor grew concerned about the unkempt condition of the lawn and an accumulation of mail in the mailbox and knocked on the door and rang the bell.

When that brought no response, the neighbor went to the back and saw the body of the dog lying in an enclosed porch. The neighbor then called police, who arrived about 5 p.m.

When the doorbell was again unanswered, police kicked open the door and found the bodies.

Neighbors said the most recent residents of the house had arrived about five months ago and little was known about them.

Police said the bodies of the man and woman were taken for autopsies to the state medical examiner's office in Baltimore. They said they would try to determine their identities through fingerprints.

Four vehicles, which were parked at the house and which included a BMW and a Mercedes, were impounded by police for investigation, authorities said.