Unintentional murder is not a contradiction in terms.
I think it is a contradiction.
Murder is the killing of a human being with intent to kill.
Without intent to kill, you just have manslaughter.
If it's not illegal, it's just homicide.
Felony murder is an exception, that just requires you to get somebody killed by doing a dangerous crime.
But if Chauvin didn't intend to kill, and if he isn't charged with felony murder, then the prosecution will have to prove intent to kill to get a murder conviction.
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All of the above is dated, but I assume that murder still requires intent to kill.