BOSTON -- A South Boston woman has been charged with first-degree murder in the fire deaths of two young sisters who were trapped inside their burning townhouse on West Sixth Street in early April.

A Suffolk County grand jury indicted Nicole Chuminski, 26, in the April 6 deaths of Acia Johnson, 14, and her 2-year-old sister Sophia.

She was also charged with a single count of arson for allegedly setting the fire and two counts of assault and battery in connection with fire- and smoke-related injuries to the victims’ mother and brother, who were also injured in the deadly blaze.

The grand jury investigation suggested that Chuminski and the victims’ mother had an argument in the hours preceding the fire, according to the DA's office.

Additional evidence placed Chuminski near the scene around the time of the fire and traces of an accelerant were recovered from Chuminski’s clothing which were consistent with an accelerant discovered on the door frame of the burned building, the DA said.

Chuminski was arrested May 9 and held without bail at her May 12 arraignment in South Boston District Court. The indictments move her case to Superior Court, where all homicide cases are adjudicated.