"There are perhaps as many different types of spies as there are criminals," Crossle said at his next session with Russell. "In fact, by its very nature, espionage necessitates a technique and a disregard of law which imposes on its members the morality - or rather I should say the lack of morality - of the underworld."

"More than one crime during the war was traced definitely to spy activities which, for obvious reasons, were never made public. The most notorious of these, perhaps, was the murder of Roy Hartwell. Hartwell was the typical man-about-town whose escapades were frequently featured in the press. His bachelor quarters in a penthouse on West Thirty-Sixth Street were the scene of many drinking and gambling parties."

"His body was discovered there one morning in an armchair, a bullet hole through his head. The fact he wore evening clothes made it evident he'd been shot shortly after he came in the night before. A packed suitcase also indicated that he was about to leave the city."

"The crime, at first sight, presented no extraordinary elements. Hartwell's mode of living made him many enemies - he was reputed to have welshed on one or two large gambling debts and his fickleness in love had repeatedly caused him trouble. But a slip of paper in one of his pockets changed the whole aspect of the case. It bore a typewritten message in cipher, which was turned over to us by the police commissioner."

"And that," Crossle concluded, passing the slip over, "is your next problem."

GSVNY UYPCN EWMSP HMCHR BQDSH NMRBG QYNNC YPZSM LAC.

Solution