so investigators seized it and turned it over to gordon mitchell, an expert in the growing field of computer forensics. mitchell copied bob durall's hard drive to examine the information on it without altering the original data. >> this is an important process where they can actually discover, is there something going on here, or is bob just a nice guy? >> mitchell found evidence that bob deleted certain files, but they were still on the hard drive. that's because computers don't erase files. they just mark the space occupied by those files for reuse. >> a lot of the deleted files are simply information left in place. >> the deleted information revealed that bob was dating women he met on the online dating service match.com and was doing so at the same time his wife, sherry, was dating kevin johnson. bob's profile on the dating website was also revealing. >> mr. durall portrayed himself as a man who was living separately from his wife and who was completely unburdened by any other romantic or personal attachments and was open to a relationship with the appropriate woman. >> in e-mails to pro