 In early 1996 , former FBI hostage negotiator and criminal profiler Clinton R. Van Zandt was contacted by an investigator working with Tony Bisceglie . Bisceglie asked Van Zandt to compare the manifesto to typewritten copies of handwritten letters David had received from his brother . Van Zandt 's initial analysis determined that there was better than a 60 percent chance that the same person had written the letters as well as the manifesto , which had been in public circulation for half a year . Van Zandt 's second analytical team determined an even higher likelihood that the letters and the manifesto were the product of the same author . He recommended that Bisceglie 's client immediately contact the FBI . 
