The Hennepin County Attorney’s Office will not file charges in the fatal stabbing this week on a Blue Line light-rail train in Bloomington.

In a news release, the office said the 67-year-old man suspected in the Thursday stabbing will not be charged “as we would be unable to disprove a claim of self-defense.”

The stabbing occurred about 1 a.m. Thursday after a verbal altercation between two men as the northbound train left the Mall of America station. They exchanged words, which led to a physical fight. At one point one of the men pulled a knife, officials said.

Anthony Demetrius Watson, 45, of Minneapolis, was taken to HCMC in Minneapolis, where he died.

Metro Transit and Bloomington police responded to the scene and arrested the alleged assailant when the train stopped at the 28th Avenue Station.

The suspect was initially taken to the Hennepin County jail, where he was being held on probable cause murder. The Star Tribune generally does not name suspects if they are not charged.