SALT LAKE CITY -- Admitted booby-trap bomber Mark Hofmann used biofeedback and self-hypnosis to put on a 'performance' that gave him the rare power to beat a lie detector test, a University of Utah polygraph expert said Tuesday.
Charles Honts, a university professor, administered a polygraph test to Hofmann in November 1985, and concluded, along with other experts at the time, that the documents dealer was innocent of the Oct. 15, 1985, bombings that killed Steve Christensen and Kathy Sheets.
Honts recently visited Hofmann at the Utah State Prison, where he is serving sentences of up to life on his guilty pleas to the bombing murders and to theft counts in connection with forged documents.
Asked how he fooled the lie detector, Honts said Hoffman discussed the two skills that he felt helped him beat the polygraph.
'First, and I think this is the most important skill, he has a lot of experience with biofeedback,' Honts said. Hofmann said he constructed a blood pressure monitor from a kit several years ago, and practiced with it until he could change his physiological signs at will, Honts said.
In addition, Hofmann said he practices self-hypnosis and uses it every day, Honts said. The admitted killer saidhe was able to split his personality.
'He said there were two individuals there. One who knew he was lying. The other, the person who was taking the test, thought he was innocent,' Honts said.
'A performance, that's what it was,' Honts said.