supervisor for pottawattamie county.y. >> reporter: i mean, how much stuff did you have to go through? >> it was um, it was terabytes worth of information. maybe about three dozen email accounts, a dozen facebook accounts and a number of different apps. >> reporter: and in his tiny office kava sat, hour after hour, late into the night, deciphering enormous amounts of digital data. >> it might take her five minutes to create a fake email account. it might take me you know 15 hours to prove that it's actually her. >> reporter: among those many accounts was a youtube account with this video. >> the title of the video is "husband's cheating place." >> reporter: and that video -- showed the apartment of dave kroupa. but the ip address where that video was uploaded? was where liz lived. >> so again it was another arrow pointing at liz. >> reporter: painstakingly, arrow by arrow, anthony kava compiled the evidence. his conclusion -- every one of those threatening emails, and texts, and facebook posts and youtube videos, linked