Jungk's book was influential on Frayn's play via the work of journalist Thomas Powers, who repeated the claims that Heisenberg had sabotaged the German nuclear program in a 1993 book, further asserting that the Copenhagen meeting was actually a counterintelligence operation to let Bohr in on what the Nazis were up to. Frayn's play, which portrays Powers' theory sympathetically as a possible interpretation of the meeting, brought more attention to what previously had been a primarily scholarly discussion. After the play inspired numerous scholarly and media debates over the 1941 meeting, in 2002 the Niels Bohr Archive in Copenhagen released to the public all sealed documents related to the meeting. Among the documents were the unsent letters Bohr drafted to Heisenberg about Jungk's book and other topics. Many historians have strongly criticised the play on the basis of the released letters, contending: