Prosecutors say they can't prove it wasn't self-defense.

Prosecutors have decided against filing charges in a fatal stabbing on a Blue Line light rail train in the early hours of Thursday morning.

Anthony Demetrius Watson, 45, of Minneapolis, died in Hennepin County Medical Center from multiple sharp force wounds, following an altercation on the train.

A 67-year-old man was being held on probable cause murder, but the Hennepin County Attorney's Office announced Friday afternoon he would not be charged.

"After reviewing the case, the Hennepin County Attorney's Office will not be filing charges in the Bloomington light rail stabbing that occurred Jan. 23 as we would be unable to disprove a claim of self-defense," a statement from Mike Freeman's office read.

Watson had been involved in a verbal altercation with another man on the Blue Line that turned violent, with the other man allegedly pulling a knife.

Police found Watson wounded when the train stopped at the Mall of America station.

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