In fact, he had been traced within ten minutes of the murder on the way to the scene of the homicide.

But some little link was lacking and the brewery officials called in the agency.

The first thing the superintendent did was to look over the engineer.

At first sight he recognized him as a famous crook who had served five years for a homicidal assault! One would think that that would have settled the matter.

But it didn't! The detective said nothing to his associates or employers, but called on the engineer that evening and had a quiet talk with him in which he satisfied himself that the man was entirely innocent.