I stared at him amazedly.

"Someone has been at the lock!" I cried. "But that is impossible,
with two men in the room--unless--"

"They were both knocked on the head!"

"Both! But by whom! My God! They are not--"

"Oh, no! It was done artistically. They both came round about
four o'clock this morning."

"And who attacked them?"

"They had no idea. Neither of them saw a thing!"

My amazement grew by leaps and bounds. "But, Bristol, one of them
must have seen the other succumb!"

"Both did! Their statements tally exactly!"

"I quite fail to follow you."

"That's not surprising. Listen: When I got on the scene about five
o'clock, Marden and West, the two C.I.D. men, had quite recovered
their senses, though they were badly shaken, and one had a cracked
skull. The constable was conscious again, too."

"What! Was he attacked?"