peace got into trouble with the law. williams was accused of stealing three computer monitors for his personal use from the county i.t. department. here s surveillance video showing him carrying boxes of computer equipment. it just seems odd that someone like that would bother to steal a few computer monitors. exactly. it was just kinda shocking that someone would go and do that. reporter: williams found himself on the wrong side of this police interrogation. okay, judge, before we get started, i m gonna read the miranda warning. you re an attorney, you re a judge, so you know as well as i do. i know you gotta read. i understand. reporter: williams tried to explain he took the monitors because he claimed he needed new equipment for his office but never got it. that s been an ongoing kind of thing, where i d tell the i.t. people that i need to keep improving things. i understand. but you hadn t put any kind of written request in, nothin like that s been documented at
to parole out. somebody held the grudge, and got out and wanted him. reporter: even though investigators were convinced he was murdered because of his job as a prosecutor they doesn t stop there. we have to interview friends and family members and associates. reporter: mark was a tea tottler and he did not have a wife or kids. there was nothing there, he loved his mother who lived in dallas, he spent time taking care of her and taking her to dinner. reporter: all the initial checks in to his professional and personal life was not panning in. frustration was setting in. the cases get harder to solve after the first 48 hours. two full days in, mark s murder had reached that cross-road and investigators were searching desperately for a break. understands tell us tonight there s simply no promising leads in the case right now. this murder is turning in to a who done it.
and and they began finding gun parts. reporter: gun parts. some very specific gun parts that appeared to match the type of automatic weapon used in the mclelland killings. and at the same time, the fbi discovered williams had done computer searches on hasse and mclelland before the murders. specifically told them that he had not ever searched the two victims before the murders. now you ve got him lying? yeah. reporter: that lie and those gun parts were enough to get a warrant for a more thorough search of his house. investigators, including a crack fbi evidence team, were back the next day. they went room to room, then to the garage. and, bingo! in a filing cabinet in the garage there was a manual for a ford crown vic. and there was also a title to a crown vic. reporter: the task force, of course, had been looking for a crown victoria. this one was registered under a
injury. reporter: did he fly again? he did. reporter: why would you want to fly again? he almost died. he wanted to be the person he was before, it s like being thrown from a horse. reporter: he did. he did, and it took a long time. reporter: they got a kick out of his weakness, his love for sugary snacks. he a sweet tooth and he would mostly eat everyone s stuff. so, if we had weekly prosecutor meetings every monday and we would get doughnuts for them and he would get there first and steal my blueberry doughnut. mark and shannon got a new boss that seemed to fit right n newly elected district attorney. mike mcclelland. his stepdaughter said he loved the job. i think he did embrace being a leader and he enjoyed the people he worked with. he would talk about this person
did this and i was proud of them. this person did this and i was proud of them. he came and took it over. reporter: was he tough? he was not tough on us at all. the greatest thing about him, he let us do what we do best. reporter: he formed a relationship with mark. mark was his best friend in the office. they were very close. reporter: mark s wife fit in, she was like a den mother, worked as a nurse and found time to bake cakes and cookies for the staff. she was a avid quilter who loved to make gifts for her husband s co-workers, including shannon now married with two children. she brought in fabrics to show me, is this going to match the nursery. then she quilted it and it was stunning. it was beautiful. reporter: that s how it was, a humming, happy office in a small town. until january 31st, 2013 just before 9:00 a.m. at that moment