Claim: They Used Dark Forces is the 511 page WWII novel by Dennis Wheatley published by Hutchinson, a former British publishing firm currently an imprint which is ultimately owned by Germany's Bertelsmann.
Evidence: 511 pp Dennis Wheatley World War II novel Hutchinson Hutchinson was a British publishing firm which operated from 1887 until 1985, when it underwent several mergers. It is currently an imprint which is ultimately owned by Bertelsmann, the German publishing conglomerate.