The Massachusetts State Police trooper who fired his rifle during a police confrontation in which a Cape Verdean ATV driver was injured in Boston on Saturday has a long history of posting racist and profane comments on a website called MassCops, including some in support of police officers who shoot suspects.

“Note to [expletive] scumbags!” wrote Trooper Matthew Sheehan, using the screen name “Big Irish,” in a July 2012 posting about an incident in Worcester in which a state trooper shot and killed a man who allegedly drove at him. “You try and run us over and you will die!!!! Good shoot ALL DAY LONG!!!!!!!”


Sheehan sprinkled his posts as Big Irish with biographical information that the Globe verified as Sheehan’s, including his birthday, hometown, and work history. He mentioned taking a Globe reporter on a ride-along and was photographed for the story. Two people with knowledge of the situation also identified Sheehan as Big Irish.