tinnes, at some point did your relationship with lisa techel become sexual? re we? >> no, sir. >> we're talking about actual sexual intercourse correct? >> yes, sir. >> reporter: for lisa's father, the revelation that his daughter had a lover was the cruelest blow yet. >> the first emotion i had is, "why? why, lisa?" you know? and my second thought is, "i don't wanna tell amy 'cause i know she's not gonna be happy." >> reporter: does it taint your memory at all? >> really, what it did for me more than anything is, i have so many more questions that i'll never get the chance to ask her. i mean, i love lisa and she was a human being and she made mistakes. >> reporter: the graphic testimony about lisa's affair, and how police overlooked it, fit perfectly with the defense's theme of a botched investigation and a rush to judgment against seth. >> here's a legitimate suspect that should have been investigated. >> reporter: investigators never spoke to jason while they were building their case against seth. prosecutors finally contacted him just days before the third