"Stubborn?" repeated Feathergill lugubriously. "It's downright impervious. Heath is spinning round like a turbine. He was called off the Boyle case, by the way, to devote his talents to this new shocker. Inspector Moran arrived ten minutes ago, and gave him the official imprimatur."
"Well, Heath's a good man," declared Markham. "We'll work it out. . . . Which is the apartment?"
Feathergill led the way to a door at the rear of the main hall.
"Here you are, sir," he announced. "I'll be running along now. I need sleep. Good luck!" And he was gone.
It will be necessary to give a brief description of the house and its interior arrangement, for the somewhat peculiar structure of the building played a vital part in the seemingly insoluble problem posed by the murder.
The house, which was a four-story stone structure originally built as a residence, had been remodelled, both inside and outside, to meet the requirements of an exclusive individual apartment dwelling. There were, I believe, three or four separate suites on each floor; but the quarters up-stairs need not concern us. The main floor was the scene of the crime, and here there were three apartments and a dentist's office.
The main entrance to the building was directly on the street, and extending straight back from the front door was a wide hallway. Directly at the rear of this hallway, and facing the entrance, was the door to the Odell apartment, which bore the numeral "3." About half-way down the front hall,
