attorney kathleen zellner was determined to get him out. >> nothing's as riveting as this, when the trial's's been lost, and you've got something that's the ultimate challenge, i think. >> i said, that's the woman that's going to get steven out of prison. >> zellner specializes in wrongful conviction cases and says she's freed 18 defendants, including ryan ferguson. sandy contacted her and she joined the case not long after "making a murderer" came out. we caught up with zellner at the correctional institute when she paid a visit to avery in 2016. >> million dollar question. do you think you have new evidence that could free steven avery? >> we do, yeah. >> zellner invited "dateline" into this war room she created in her office outside chicago. all dedicated to the avery case. >> do we know if that was tested? >> and she even showed us that rav4 she brougought to get a be understanding of teresa's vehicle. then in august 2016, to much media fanfare, she filed a motion in manitowoc county court, seeking new testing of the evidence. >> we're going to find out one way or the other was the evid