``Through a door conveniently unlocked,'' Madden supplemented.

``That damn door,'' said the police chief.

``A gift horse to be viewed with suspicion.'' Madden's dark face wore a meditative look. ``If there was collusion between an outside murderer and a member of the household it would be an elementary precaution to check on the door later. And it makes a very poor red herring for an inside job. Much better to break a cellar window.''

``Don't forget, there was the hope it would pass for a natural death,'' Pauling reminded him.

``Well, with a house as big as that there must be at least one cellar window that wouldn't be noticed right away unless there was a police investigation.''

``Yeah. And a pane of glass isn't hard to'' --

The telephone interrupted him. He scooped up the receiver and said, ``Police chief,'' into the mouthpiece, and then, ``Oh yes, Mr. Benson. I was hoping I'd hear from you today.''

With his free hand he pulled a pad and pencil toward him and began to make notes as he listened, saying, ``Uh-huh'' and ``I see'' at intervals.

At last he said, ``Well, thank you for calling, Mr. Benson. Although there was no doubt in my mind and we've been handling it as one I'm glad to have it made official.''

He hung up. ``Coroner,'' he said to Madden. ``He's just heard from the pathologist who says Mrs. Meeker apparently died from suffocation.'' Pauling looked at his notes. ``Many minute hemorrhages in the lungs; particles of lint and thread in the mouth and nostrils. Scrapings from the bed linen identical with the lint and thread found in the nasal and oral cavities. No other cause of death apparent. Trachea clear of mucus and foreign objects. Brain examined for thrombosis, clot or hemorrhage. No signs of these, no gross hemorrhage of lungs, heart, brain or stomach.'' He paused. ``That's about it. Oh, the time of death. The duration of the digestive process varies, the pathologist says, but the empty stomach and the findings in the upper gastrointestinal tract indicate that Mrs. Meeker died several hours after her seven o ' clock dinner. Probably around midnight, give or take an hour either way.''