e old catchword, "Honour among thieves,"
was one he had little reason to believe in. There was always a trickle
of information into headquarters by subterranean ways. The commonplaces
of crime were effectively looked after. Murders are the exception in
criminal investigation work, and while other crimes may be dealt with by
certain predetermined if elastic rules, homicide had to be considered
differently. Yet Foyle had cause to think that there might be little
harm in setting to work the underground agencies which at first sight
seemed to have little enough in common with the mystery of the rich
Robert Grell. These spies and informers would try to cheat and trick
him. Some of them might succeed. It would cost money, but money that
might not be wasted.

Four of the five chief detective-inspectors who form the general staff
of the C.I.D. were in the room, among them Wagnell, who had passed a
quarter of a century in the East End and knew the lower grades of
"crooks" thoroughly, collectively, and individually.

Foyle shut the door.

"I wish some of you would pass the word among our people that we will
pay pretty handsomely for any one who puts us on to the gang mixed up in
this Grell business. Word it differently to that. You'll know how to put
it. You might get hold of Sheeny Foster, Wagnell, or Poodle Murphy, or
Buck Taylor. They may be able to nose out something."

"Buck was sent up for six months for jumping on his wife," said Wagnell.
"I haven't seen Sheeny lately, but I'll try to get hold of him, and I'll
have the word passed along."

So, having made the first step in enlisting a new and formidable force
of guerillas on the side of the law, Foyle went back to his office to
revolve the problem in his brain once more.

His thoughts wandered to Sir Ralph Fairfield. Here was a man whose
services would be invaluable if he could be persuaded to help. Grell
knew him; trusted him. Foyle was a man who never neglected the remotest
chances. He deemed it worth trying. True, so far as their encounters
were concerned, Fairfield had not been encouraging. He would probably
need delicate handling. Foyle wrote a note, scrutinised it rapidly, and,
going out, gave it to a clerk to be sent at once by special messenger.

"Mr. Heldon Foyle presents his compliments to Sir Ralph Fairfield and
would be obliged if he could see him at his office at six o'clock this
evening, or failing that, by an early appointment, on a matter of urgent