Termin bardzo powszechny, często w cudzysłowie.

http://histclo.com/essay/war/ww2/code/sci/ger/abw/abw-ruk.ht...

"The spies were given the choice of turning or bring tried and shot. This was MI-5's Double Cross system. The Germans were not aware of their failure because the turned agents kept reporting to Germany as if nothing had happened."

http://articles.latimes.com/1995-11-02/local/me-63823_1_ames...

"What has now been learned is that at least 100 other active or potential CIA agents in the Soviet Union were fingered by Ames and then "turned" by Soviet intelligence agencies."

http://www.xenu.net/archive/go/felix/ch_i8.htm

"The commonest substitute for planting one's own agent is the "turning" of an enemy agent. Turning an agent, that is to say, convincing a man working in another cause that he should change sides and continue active in the conflict, with all the added risks involved, is clearly a psychological operation of immense complexity."

http://www.mspb.gov/netsearch/viewdocs.aspx?docnumber=256024...

"...that appellant had been successful in turning an agent of a hostile intelligence agency into a "double agent."

https://fas.org/spp/eprint/at_sp.htm

"If an enemy discovers satellites which the owner believes he does not know of, he can then use those satellites as channels of disinformation which will probably be believed -- the modern technical equivalent of 'turning' an agent. In addition, of course, discovered satellites can be targeted for attack."