"Quite right," said Gatton shortly, "and now here are the keys which
you returned to the depôt this morning."

From his pocket the Inspector produced a steel ring bearing a large
and a small key which I recognized as that which had hung from the
lock of the garage door on the previous night.

We walked along to the garage and Inspector Gatton placed the key in
the lock; then turning to Bolton:

"Now," he directed, "show us exactly what you did."

Bolton replaced his bowler, which hitherto he had carried in his hand,
hesitated for a moment, and then unlocked the door.

"Of course I had my lantern with me last night," he explained, "and
this gentleman and myself stood looking in for a moment."

"Mr. Addison has already described to me exactly what he saw," said
Gatton. "Show us what you did after Mr. Addison left you."

Bolton, with a far-away look in his eyes betokening an effort of
retrospection, withdrew the key from the lock and entered the garage,
Gatton and I following. There was a sky window to light the place, so
that when Bolton reclosed the door we could see well enough. His
movements were as follows: Relocking the door from the inside, he
walked slowly along to a smaller door at the opposite end and with the
other key attached to the ring unfastened it.