The Killer Speaks is an American documentary series on A&E (also available on Netflix) that debuted in April 2013. It features actual convicted felons as they describe their crimes step-by-step, leaving no details out. The story is also told through interviews with investigators, family members, and others intimately involved in the case. John X. Kim is the senior Executive Producer.
https://www.youtube.com/watch?v=F14Uk-MaXa8