a ray of light coming from the keyhole of the Professor's study.
That surprised me, because he never worked as late as that before.
I thought it over a moment, then I crept up and looked through
the keyhole."

"And what did you see?"

"He sat at his desk, quite quiet. So I felt easy again, and went
off to bed."

"Why didn't you go into the room?"

"I didn't dare, sir. The Professor never wanted to be disturbed
when he was writing."

"Well, and this morning?"

"I got up at the usual time this morning, set the breakfast table,
and then knocked at the Professor's bedroom door to waken him. He
didn't answer, and I thought he might want to sleep, seeing as it
was Sunday, and he was up late last night. So I waited until ten
o'clock. Then I knocked again and tried the door, but it was locked.
That made me uneasy, because he never locked his bedroom door before.
I banged at the door and called out, but there wasn't a sound. Then
I ran to the police station."

Horn was evidently as alarmed as was the young valet. But Muller's
cheeks were flushed and a flash of secret joy, of pleasurable
expectation, brightened his deep-set, grey eyes. He sat quite
motionless, but every nerve in his body was alive and tingling. The