What are some really great Crime Documentaries. Exclude The Thin Blue Line. It's great but I have seen it.?

Also, exclude The Staircase Murder (great, but I have seen it). You can also include any other documentaries that are really interesting. I am majoring in Crim. Justice so those documentaries are really interesting to me, but any interesting documentary is great. If you know of any good 'end of days' documentaries or something, those would probably be cool. Whatever, just as long as they are truly interesting and not ..'Eh'