BOSTON — A Boston man has been convicted of fatally shooting a Maine woman as retribution for missing heroin.

A Suffolk Superior Court jury on Tuesday found 27-year-old Amos “Ace” Don guilty of charges including first-degree murder for the August 2009 slaying of 29-year-old Erica Field of Lewiston, Maine.

Prosecutors say Don was a heroin dealer who enlisted Field’s boyfriend to help him sell drugs in the Lewiston area. When some heroin went missing, Don suspected Field’s boyfriend. The three drove to Boston under the guise of obtaining more drugs. Authorities say Don made them drive to an isolated area where he shot both. The boyfriend survived.

Don, who is already serving a 6 1/2 -year sentence on a federal gun conviction, faces a mandatory sentence of life in prison without parole.