BOSTON — A Dorchester man will spend the rest of his life behind bars for killing a Lewiston woman in 2009.

Amos “Ace” Don, 27, was found guilty Tuesday of first-degree murder in the shooting death of Erica Field, 29. A day later, he was ordered to spend the rest of his life in prison.

Assistant District Attorney Ian Polumbaum recommended additional terms of 15 to 20 years in state prison for armed assault with intent to murder and 13 to 15 years for aggravated assault and battery with a dangerous weapon, of which Don was also convicted. A judge imposed the requested sentences, but ordered them to run concurrent with the life term.

“This was a cold-blooded murder committed because one man valued drug money more than human life,” Suffolk County District Attorney Daniel F. Conley said. “I can only hope that Erica’s family can find some small measure of satisfaction that justice was done on her behalf.”

Don also was convicted of aggravated assault, battery with a dangerous weapon, armed assault with intent to kill and illegal possession of a firearm in the nonfatal shooting of Field’s boyfriend, 32-year-old Shameek “Jo Jo” Garcia.

Prosecutors presented evidence at the trial showing that Don often traveled to Lewiston during the summer of 2009 to sell drugs and that he enlisted Garcia as a local dealer. When an amount of heroin went missing that August, Don was told not to trust Garcia.

On Aug. 25, Don, Field and Garcia drove to Boston for more drugs, according to testimony at trial. Don told Garcia to drive to a Norwell Street truck storage lot. Don sat in the back seat; Garcia and Field sat in the front. Don shot Garcia once in the head and shot Field twice, according to Renee Nadeau Algarin, a spokeswoman at the Suffolk County District Attorney’s Office.

Field, who worked at a hamburger stand in Lewiston, died at the scene.

In a news release Wednesday, Conley lauded the Lewiston police detectives who worked hand in hand with Boston police and Suffolk prosecutors throughout the investigation.

“Jurisdictionally, this wasn’t their case,” Conley said, “but they gave it everything they had for Erica and her family.”

The jury deliberated for a day before finding Don guilty on all counts.