Doesn't matter who shot it, laws the law, and they decided to push it rather than give up a trophy for a night. Serves em' right for not being able to properly bring down an animal.
MN DNR:
SHOOTING HOURS
Shooting hours for big game are ½ hour before sunrise to ½ hour after
sunset.
The Minnesota DNR investigated the attack, as they normally do in incidents like these, and no charges were filed. So unless you have evidence that the Bear was shot illegally, your supposition is baseless...man crushes and lucky fools notwithstanding.
Time-frame note: From what I can gather, this event took place on September 27th and was first reported by McKenzie Gernes of KSTP - http://kstp.com/article/stories/s3573176.shtml.