>> mac, the father of three daughters and a son, asked the couple to understand his situation. >> i said, listen, i said, i'm going to do everything i can, but i'm kind of limited to what i can do, because of my workload that i have now. linda was great. she even said i'll do anything. i've got secretarial skills, i can help you file, type up things, do this and do that, just so i could spend more time dealing with her family's case. >> linda zarzycki, the stepmother, would go to the eastpointe police station on her lunch hour to pore through the case files. she'd suggest theories to mac. >> and he'd say, yep, he thought of that too but kept running into brick walls. he couldn't seem to make progress. >> but in 2004, the brick wall was about to start crumbling because a new player, a completely unlikely partner for the veteran detective, had talked herself on to the case. she wasn't even a cop, she was a 23-year-old college intern with