Suffolk County District Attorney Daniel F. Conley today announced convictions for murder and other offenses in the trial of a woman who started a South Boston house fire that claimed the lives of 14-year-old Acia Johnson and her 2-year-old sister, Acia.

A Suffolk Superior Court jury late this afternoon found NICOLE CHUMINSKI (D.O.B. 5/19/82) of South Boston guilty of two counts of second-degree murder for the children’s deaths. Jurors also convicted her of arson for setting the blaze and two counts of assault and battery with a dangerous weapon – smoke and flames – for injuries sustained by the girls’ mother and brother, who survived the fire.

“Throughout this investigation and prosecution, our goal was to speak for two murdered children,” Conley said. “Suffolk prosecutors, Boston Police detectives, Boston firefighters, State Police chemists, our victim-witness advocates, and countless others worked toward the result we reached today. But as satisfied as we are with these verdicts, we know they will never replace the beautiful lives that were snuffed out on April 6, 2008.”

Suffolk Superior Court Judge Frank Gaziano will sentence Chuminski at 9:30 on Thursday morning. Chuminski faces a mandatory life term for each murder conviction.

During 10 days of testimony, Assistant District Attorney David Fredette of Conley’s Homicide Unit and Assistant District Attorney Julie Higgins of the district attorney’s Domestic Violence Unit proved that Chuminski and the victims’ mother attended a wedding on the afternoon and evening of April 5, 2008.

The two became embroiled in a conflict at that wedding and left separately. Chuminski, furious at being humiliated in front of her family, returned to the victims’ West 6th Street home in the early morning hours of April 6. Using an accelerant, she set the house on fire and fled. The fire quickly consumed the building, trapping Acia and Sophia inside. The girls’ mother and brother were able to escape the conflagration.

When Boston firefighters finally doused the blaze, they entered and found the two girls’ remains. They had died in each other’s arms.

Catherine Yuan was the DA’s victim-witness advocate assigned to the case. Chuminski was represented by attorney William White, Jr.