BOSTON — A Quincy bouncer who killed an Irish carpenter with a single sucker punch on St. Patrick's Day has been sentenced to three to six years in state prison, nearly three years after the fatal attack on one of Boston's busiest streets.

Sanusi Sadiq, 31, struck Barry Whelan, 46, from behind during an argument on Winter Street in Downtown Crossing on the evening of March 17, 2023. Whelan, who was intoxicated, fell backward and hit his head on the pavement. Sadiq walked away. Whelan never got back up.

Whelan, a Dublin native who emigrated to the United States in 2002, had been living in Woburn. Coworkers said he had been looking forward to celebrating the holiday of his homeland and was excited to have a Guinness on St. Patrick's Day. He never got the chance.

Surveillance cameras captured the encounter near a Winter Street ATM around 9 p.m. The footage showed Whelan approaching Sadiq and the two men arguing before Sadiq struck him in the head from behind with his right arm. Sadiq, who was on his way to work at a nearby nightclub, told investigators the two did not know each other and described the exchange as racial in nature, claiming Whelan used racist slurs.

Judge Mary Ames sentenced Sadiq in Suffolk Superior Court on Monday, calling the killing "an avoidable tragedy because Mr. Sadiq had every opportunity and obligation to walk away."

Prosecutor Jillian Bannister had sought five to seven years. Defense attorney Michael Chinman pushed for two, calling Whelan the "provocateur" in the encounter. Ames split the difference at three to six.

At sentencing, Sadiq told the court: "I allowed words to lead me to an impulsive moment." He called the killing "a moment of poor judgment and decision making" that "forever changed the trajectory of my life."

Suffolk District Attorney Kevin Hayden was more blunt: "Some bad decisions nearly three years ago resulted in one person losing his life, another person losing his freedom, and many friends and family members left with eternal loss and sadness."

Whelan's brother, Darren, addressed the court: "Barry was a wonderful human being who was loved deeply."

Those who worked alongside Whelan remembered him as a hard worker who was passionate about his job and incredibly proud of his Irish roots. His employer dedicated a renovated church area in his memory, complete with a plaque. "This is how much Barry meant to us," the employer said.