Here are some other (non Zellner) documentaries that you may like:

Fear of 13 https://www.netflix.com/search?q=fear%20of%2013&jbv=80099305&jbp=0&jbr=0

An Unreal Dream: The Michael Morton Story https://www.amazon.com/Unreal-Dream-Michael-Morton-Story/dp/B011P4ENY8/ref=tmm_aiv_swatch_1?_encoding=UTF8&qid=&sr=

The Staircase https://www.amazon.com/Chapter-1-Crime-or-Accident/dp/B00V3N0JR2/ref=sr_1_1?s=instant-video&ie=UTF8&qid=1484698467&sr=1-1&keywords=the+staircase

The Jinx - The Life and Deaths of Robert Durst https://www.amazon.com/Chapter-1-Body-Bay/dp/B00URDK8SY/ref=sr_1_1?s=instant-video&ie=UTF8&qid=1484698532&sr=1-1&keywords=the+jinx

Murder on a Sunday Morning (as others have recommended) https://www.youtube.com/watch?v=FcomFAob90k