Two hours went by and still the detective kept to his post.  He was used to waiting—­had he not waited in the bitter cold six hours to clear that poor Jew?—­and he knew that sooner or later the man calling himself Jack Watkins would reappear.

A light flared up in the library and then was turned lower.  He crept to the window and looked in as before.  The strange man was at the safe, working the combination knob backward and forward.

In spite of the seriousness of the situation, Adam Adams was forced to smile.  The man worked hurriedly and tried the combination a score of times.  He muttered something under his breath which may well be omitted from these printed pages.  He even got into a heavy perspiration and had to pause to wipe his forehead with his handkerchief.

“Hang the luck!” he went on.  “I had it open before.  What’s got into the confounded combination?”

Again he tried to work the figures.  But it was all of no avail, and at last he arose, fists clenched, and with a face full of baffled anger.  He stalked around the library, gazed at the strong box several times, and then quit the apartment.

Waiting once more, the detective presently saw the man come from the house and walk toward the road.  Following, he saw the fellow hurry past the Bardon home and then into a patch of timber.  Here he had a horse, and in a moment more would have been in the saddle had not Adam Adams caught him by the arm.

“Hi! what’s this, a hold-up?” cried the man, evidently frightened.  “Let go of me!” And he tried to pull away and then attempted to draw a revolver from a hip pocket.

“Stop!  I am not going to hurt you,” was the calm reply from the detective.  “I want to talk to you, that’s all.”

“Really?” came with a sneer.  “A fine time of night to hold a man up.  Be quick, for I am in a hurry.”

“I want you to explain several things to me,” went on Adam Adams calmly.

“Explain?  To you?”

“That is what I said.  You can take your choice.  Either explain or consider yourself under arrest.”

“Eh?  Say, are you crazy?”

“Not at all.”

“An officer of the law, I suppose.”

“I am—­in a way.”

“Working on this Langmore affair?”

“Yes.”

“Have you been following me?”

“I’ve done more than that—­I’ve been watching you.”

“What!  How long?”

“Quite a long while.  I saw you in the library, twice, and down to the brook.”

The man started and was evidently much put out.  Then he forced a smile to his face.

“Much obliged for playing the spy,” he murmured.

“Down at the brook you had a pair of Miss Langmore’s shoes.  What were you doing with them?”

“Did you see me with the shoes?”

“I did, and I saw you with the silk shirtwaist.”

“Ah!  Anything else?”