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 trial started. between may of 2012 and sometime in june of 2014 no one talked to you didn t talk to anyone about this at all? no, sir. reporter: but prosecutors fought back. jason had an alibi witness his wife. they called her to the stand. do you have any memory, miss tennis, as to the whereabouts of your husband on may 26th, 2012, at approximately 5:00 a.m.? he was sleeping with me at our house. reporter: and dna testing on jason done right before trial also proved he was not the father of lisa s baby. but the defense still believed that raising the story of lisa s affair and how police never uncovered it would give jurors