never left
the bank that day; there's some devilish queer mistake here." Farrell
had identified David Cass in the bank as the man who had bet with him,
while the clerk asserted that one "Billy" Cass had made the same wager.
Hagen's description of "Billy" Cass fitted David Cass in a general way.
Again the badge number--11,785--was not Mortimer's, as registered in
Faust's book.

Crane stood pondering over the complication. He saw that until further
investigation disproved it there could be but one solution of this
intricate riddle. Billy Cass, the maker of the bet, was a race track
frequenter; David Cass was not. They must be separate personalities;
but they resembled each other; they were of the same name--they might be
brothers. Billy Cass had been in possession of the stolen note; he must
have got it from some one having access to it in the bank--Mortimer,
Alan Porter, or Cass--the cashier was quite out of the question.

The next move was to trace back through Billy Cass the man who had
delivered to him the stolen money. There was still a chance that
Mortimer, unfamiliar with betting and possibly knowing of Billy Cass
through his brother in the bank--if they were brothers--had used this
practical racing man as a commission agent. This seemed a plausible
deduction. It was practically impossible that David Cass could have
got possession of the bill, for it was locked in a compartment of which
Mortimer had the key; the latter had admitted that the keys were not out
of his possession.

This far in his hurried mental retrospect Crane spoke to Farrell: "I
think this is all we can do at present. I may find it necessary to ask
you to identify this Cass, but I hope not to trouble you any further in
the matter."

"Hang the trouble!" energetically responded Farrell, with huge
disclaiming of obligation; "I'll spend time and money to down a crook
any day; I've no use for 'em; a few of that kidney gives the racin' game
a black eye. If you need me or Hagen, just squeak, an' we'll hop onto
the chap if he's a wrong one with both feet."

Crane said nothing about the other number he had culled from Faust's
book; he said nothing about his suspicions of a brotherhood; he wanted
to go back to his quarters and think this new problem out.

What if in seeking for conclusive evidence against Mortimer he should
prove him innocent? He was treading upon dangerous ground, pushing out
of his path with a firebrand a fuse closely attached to a