Boston (AP/WBZ Newsroom)  -- A woman has been charged with setting a fire that killed two girls hours after authorities say she got into an argument with the children's mother last month.
   
Boston Police Commissioner Ed Davis tells WBZ Newsradio 1030 25-year-old Nicole Chuminski was arrested Friday in Lowell after physical evidence was recovered at the South Boston fire scene a day earlier. 

Suffolk County District Attorney Dan Conley says Chuminski was arrested on a warrant charging her with two counts of murder and a single count of arson.

Chuminski is expected to be arraigned Monday in South Boston District Court.
   
Conley says 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.

He says 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. 

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.