Police described her behavior at the time as erratic and the then-22-year-old mother was charged with first degree murder.
Firefighters faced heavy clutter conditions in the home while battling flames.
First responders were called to the 200 block of East 175th Street in the Mount Hope section at 11:21 a.m. Monday.
The 5-year-old twins who mysteriously died in their Bronx apartment had recently been violently sick, and vomiting at their school, according to police.
Police say the shooting was in self-defense, but the owner is still facing a gun charge.
Police are investigating the fatal shooting of a 23-year-old in the Bronx that may have stemmed from a botched robbery.