428 • POPOV, DUSKO
lantic convoys, and technical developments in the field of
antisubmarine warfare. Popov’s extended contact with the personable
Engels provided further evidence against him, not least by having his
dwindling funds topped up.
Popov returned by ship to New York triumphant and persuaded a
reluctant FBI to provide a transmitter, which the Abwehr was told
had been constructed by a disaffected Croat. However, the FBI re-
mained uncooperative in helping him to collect suitable information,
to the point that in March 1942 MI6 disclosed that it had learned that
the Abwehr was having second thoughts aboutivan’s loyalty, and
there was a belief that he had come under the FBI’s control since
his arrival in the United States the previous August. This unwelcome
development had been revealed inisosdecrypts that, inexplicably,
SIS had refused to share with MI5 until the following May, by which
time the situation had deteriorated into a major crisis. Finally SIS
revealed anisostext from Berlin to Lisbon, dated 21 March, instruct-
ingivan’s handler to test him with a question about his salary.
Once again, Popov was running low on funds, had failed to pay
several overdue bills, including one on his telephone, and the FBI
refused to finance his extravagant partying. He replied to the query
from Lisbon entirely unaware that it had been designed to confirm
his bona fides and was not told that anotherisosintercept from Ber-
lin, dated 5 May, advised that the Abwehr’s Luftwaffe branch had
concludedivanhad been ‘‘turned.’’ In August an exasperated FBI
asked MI6 to withdraw Popov, and two months later he returned to
Portugal, having been warned by BSC that he might receive a less
than warm welcome. Ignorant of the full circumstances—or that the
Abwehr had become very suspicious of him—Popov put on a bravura
performance in Lisbon, complaining that German parsimony had
handicapped his ability to fulfill his mission, and was rewarded with
a new assignment in London and $20,000. Naturally, these events
were monitored throughisos, although Popov was never indoctri-
nated into the source used by MI5 to check on his status and integrity.
WhenSir John Masterman’s bookThe Double Cross System in
the War of 1939 to 1945was published in 1972, Popov recognized
himself in the role of the double agent codenamedtricycle. This
prompted him to publish his own account, in which he changed sev-
eral names but quickly found himself in trouble with two of his sub-