Its more of a technicality than anything. He was charged with the wrong crime,
The third degree murder charge does not meet the required criteria of "evincing a depraved mind".
The second degree murder charge does not meet "while committing or attempting to commit a felony" In this case a separate felony must committed and must be something other than the death itself, such as a theft, etc.
While the above second degree manslaughter charge applies correctly, first degree would have been more appropriate.
The most appropriate charge is:
609.20 MANSLAUGHTER IN THE FIRST DEGREE.
Whoever does any of the following is guilty of manslaughter in the first degree and may be sentenced to imprisonment for not more than 15 years or to payment of a fine of not more than $30,000, or both:
(2) violates section
609.224 and causes the death of another or causes the death of another in committing or attempting to commit a misdemeanor or gross misdemeanor offense with such force and violence that death of or great bodily harm to any person was reasonably foreseeable, and murder in the first or second degree was not committed thereby;