Spoiler:
I just watched episode 1. The show is very well done. Really good producers and moviemakers. Here are my biases be I give my thoughts. 1) I was part of the LAIP (Legal Assistance to Institutionalized Persons) program at the UW law school when Steven was freed so I know people who worked extensively on his case to help free him. 2) My first job as an attorney was as an assistant attorney general for the state of Wisconsin. Peg Lautenschlager was the AG who hired me, she also was the one who in the end concluded that there was no criminal wrongdoing by the Manitowoc D.A. or police. I also consider her to be a good person and a great leader.

With that, here are my thoughts. I remember in law school thinking that Denis Vogel must be an evil prosecutor. And I think this series definitely portrays him as one. In reality, I think it is much more likely that he simply put blinders on in this case and then dug himself into such a big hole that once others forced the blinders off of him he got really scared and tried to cover up in any way possible so that he would not be liable.

Steven Avery was the biggest jerkoff in Manitowoc (super small town in northern Wisconsin). He didn't simply just kill a cat, he first doused it in gasoline and then threw it in the fire. He showed signs of both previous sadistic and violent sexual behavior. And his previous arrests and convictions were likely just the tip of the iceberg in terms of his police contacts. His alibi witnesses were all part of his clan - who protect their own so thinking they were lying to protect Steven was not farfetched (and clearly the jury didn't find them credible). So the first thought of "oh it must have been Steven" after the assault occurred was probably the correct one to have.

However, should Vogel have looked into Allen as a suspect? Of course. Should the whole circle jerk of showing the artist the mugshot of Avery, and then coercing the victim to think that that was her attacker, and then her being adamant that Avery was in fact her attacker which made everyone think they really had the right guy have happened? Of course not.

But was Vogel and the sheriff criminally liable? (i.e. did they purposely put an innocent man behind bars)? I don't think so. Are they very likely civilly liable (i.e. they should have to pay monetary damages because they screwed up their jobs so badly)? Yes yes yes.