A South Boston man was convicted on first-degree murder charges in the death of a 67-year-old Barbara Coyne.

Timothy Kostka, 30, was found guilty of breaking into Coyne’s East 7th Street home, premeditated murder and extreme cruelty in her stabbing death. Kostka will be sentenced on Wednesday. It is expected that Judge Mitchell Kaplan will sentence her to life without parole. 

“Given the facts of this case, first-degree murder was the only appropriate verdict,” District Attorney Dan Conley said in a statement. “Barbara Coyne was an innocent victim, and the man who killed her deserves nothing less than life in prison.”

During the trial, the prosecution proved that Kostka broke into Coyne’s house on April 16, 2012 and intended to steal high-end fishing equipment from her son. Coyne encountered Kostka while he went rifling through her jewelry box. Kostka then beat her and slashed her throat before continuing to search the home for more valuables, including about $100 in lottery tickets. 

A relative found Coyne and rushed her to Mass. General Hospital, where she was pronounced dead. 

Investigators were able to lift Kostka’s fingerprints from the jewelery boxes and an envelope. They also found DNA under the victim’s fingernails which belonged to Kostka. Surveillance tapes from a nearby store showed him cashing in the winning lottery tickets.

Witness testimony indicated that he used the winnings to buy drugs.