I think everyone involved is responsible. Including Amy Klobochar, who was the DA there. This probably officially sinks her chance at the VP nod by Biden, which she was probably going to get before this happened. Good news for the Witch from Michigan, I guess.
On another note, I have seen several internet commentators state that the Cop who killed the victim used to work with the victim. Which if true is very odd.
Finally, the charging document is now online. My wife showed it to me on twitter.