MANGUM, Okla. (AP) — The author of a book about a killer who escaped from an Oklahoma prison and disappeared with the warden's wife says he heard nothing indicating the woman was being held as a kidnap victim when he talked to her while the two were missing.

Charles Sasser testified Wednesday at the trial of Bobbi Parker, who is charged with assisting a prisoner to escape for allegedly helping Randolph Dial break out of the Oklahoma State Reformatory in 1994.

Sasser says he believes Parker stayed with Dial willingly and that he detected nothing unusual during their conversation.

Defense attorneys have said Dial drugged, kidnapped, beat and repeatedly raped Parker, and that she stayed with him only because he threatened to harm her family if she left.

Parker's lawyers have begun cross-examining Sasser.