BOSTON (AP) – A woman was charged Friday with setting a fire that killed two girls hours after she got into an argument with the children’s mother, prosecutors said.

Nicole Chuminski, 25, was arrested Friday on a warrant charging her with two counts of murder and a single count of arson, Suffolk County District Attorney Daniel Conley said. Chuminski was expected to be arraigned Monday in South Boston District Court.

An investigation into the April 6 fire that killed 14-year old Acia Johnson and 2-year old Sophia Johnson found that Chuminski and the victims’ mother, Anna Reisopoulos, got into an argument hours earlier, Conley said.

Chuminski also was seen near the home around the time of the blaze, and an accelerant that could have fueled a fire was found on her clothing afterward, Conley said. The accelerant was consistent with fuel that investigators found on a door frame of the triple-decker in the city’s South Boston neighborhood.

“Today we have reached a milestone, however, and we know the day is near when we will speak in court for two young children whose lives were tragically, senselessly taken, and who died with only each other to cling to in their final moments,” said Conley, who added the investigation would continue.

The early morning fire spread rapidly and engulfed the building, trapping the two girls on the third floor. Their bodies were identified through dental records.

Reisopoulos was seriously injured. Acia’s twin brother, Raymond, escaped.