I think even involuntary manslaughter needs to be committing some criminal act at the time. This looks more like a civil wrongful death claim than a criminal charge.
Here's the statute:
609.205 MANSLAUGHTER IN THE SECOND DEGREE.
A person who causes the death of another by any of the following means is guilty of manslaughter in the second degree and may be sentenced to imprisonment for not more than ten years or to payment of a fine of not more than $20,000, or both:
(1) by the person's culpable negligence whereby the person creates an unreasonable risk, and consciously takes chances of causing death or great bodily harm to another; or
(The statute then describes other cases that might be manslaughter, but none of them fit.)
I think the officer was guilty of "culpable negligience" in this case.
There's a little bit of wiggle room if she claims that she was not conscious that her actions were taking a chance of causing death or great bodily harm. i.e. she thought she had a taser, which could not cause death or great bodily harm, so therefore she was not "consciously taking a chance". I think it's a stretch, though. It would be similar to "I didn't think the gun was loaded", which would never get you off of a manslaughter charge.
At any rate, manslaughter does not require any other criminal activity.