Released, the door moved slowly, gathered speed, and shut with a slam. The latch clicked.
“So that’s it!” exclaimed the detective. “Thomas Sutton went into the closet; the door closed while he was there; he was trapped.”
Richard Sutton nodded soberly.
Cardona looked at the young man with a slight tendency toward suspicion. Richard Sutton was evidently broken by his father’s death.
The affair looked like an unfortunate accident. But the coincidence of the initialed letter — the third that had fitted in with circumstances — was too important to ignore.
Cardona began another inspection of the closet. He let the door shut with himself inside. He rapped against the barrier and called.
The noise was well muffled. Biscayne turned the latch, and Cardona emerged.
“Not much chance of any one hearing calls for help,” was the professor’s comment. Weston nodded.
“The closet is empty,” observed Cardona.
“Yes,” said Richard Sutton. “We used it only to store old books. The house was painted about six months ago. I took the books upstairs, and never brought them down.