"... Criminologist Eric Hickey, director of forensic studies at Alliant International University in Fresno, California, said he expects Hilton's predatory behavior began well before October, 2007, when the erstwhile subcontractor is alleged to have abducted and murdered avid hikers John and Irene Bryant. Transylvania (North Carolina) County Sheriff David Mahoney said there is "no question" Hilton was responsible for the elderly couple's deaths. "It's almost unprecedented to see someone go from zero to what he did," Hickey said. "I'd suspect he could be linked to several other crimes."