Michael Ahern, 46, of Dorchester, was arraigned today on charges he ran over and killed a man riding his bicycle down Morrissey Boulevard early last Friday morning.

Doan Bui, 63, was pronounced dead at the scene following the 12:30 a.m. crash near Malibu Beach. Bui was riding home from a fishing trip when he was struck from behind near the Beades drawbridge that spans Dorchester Bay.

According to DA Dan Conley's office, Ahern was arrested at his Adams Corner home on Sunday after a State Police investigation. Ahern called 911 from the scene of the Morrissey Boulevard crash and remained there until police and EMTs arrived. Ahern was also transported to Boston Medical Center and treated for cuts and bruises.

Today, prosecutors formally charged Ahern with motor vehicle homicide, operating under the influence of alcohol, operating to endanger and speeding. Judge James W. Coffey set his bail at $25,000 and ordered that Ahern's license to drive be suspended pending the outcome of the case.

Ahern is a well-known building contractor who — along with his wife— recently opened a new restaurant, The Sweet Life, in Lower Mills. Ahern has also been a key partner in another popular Lower Mills eatery, The Ledge and co-owns Slate Bar and Grill in Boston. Prosecutors say that Ahern had been drinking at Slate before the deadly crash. State Police who observed him at the scene say he was "unsteady on his feet, incoherent, and smelled of alcohol," according to DA Conley's office. Prosecutors said that Ahern refused a blood test at the hospital.

Ahern, who is represented by attorney Jeff Clifford, is due back in court on Nov. 21.