Police have been investigating the case on the theory that it was a murder-suicide committed by a troubled 14-year-old boy found dead in the apartment with a razor under his body.
The note, found Friday at the Staten Island home, had only word fragments that were legible. Police said its significance was unclear.
Police are still trying to learn exactly what happened. Autopsies Friday failed to confirm the cause of death for either the mother or the teen. Police suspect he slit his own throat.
His two sisters were found dead in the apartment Thursday with their throats slit. The boy's mother was also found dead in the apartment. A 2-year-old boy died later Thursday at a hospital.
The suspect, C.J. Jones, is described a troubled teen with a history of setting fires. Investigators suspect he killed his 32-year-old mother Leisa, 2-year-old brother Jermaine, 7-year-old sister Melonie and 10-year-old sister Brittney.
He allegedly set the fire, then committed suicide by slitting his throat too.
Investigators, however, haven't completely ruled out the possibility that the mother was the killer, and the medical examiner's office said further study was being done to determine how she and her son died.
"I don't believe this happened," said neighbor Shaquawna Meaders, who had spent the previous evening with the family. "This boy is not capable of doing such harm to his family."
The Medical Examiner's office performed autopsies on all five victims. The results were inconclusive for the Leisa and C.J. Their causes of death are pending further tests. The deaths of the three siblings were deemed to be homicides. Melonie and Brittney died of neck wounds. Jermaine died of smoke inhalation and burns.
But neighbors say C.J. was far from violent. They say the middle-schooler took care of his siblings, often shuffling them to and from day care.
Police sources say the fire was started near the front door of the family's Port Richmond apartment, so that no one could get out and firefighters would have a hard time getting in.
The tenants in the other three apartments got out safely.
Investigators say the day before the blaze, C.J. got kicked out of a public pool for setting a fire there and that in the last few days, neighbors saw him lighting paper on fire in front his apartment building.
A law enforecement source tells Eyewitness News that authorities came up with gruesome scenario for several reasons. First, C.J. was found in a back bedroom, separate from the rest of the bodies. They say the fire was set in the room where his family was found, and a straight razor was found under C.J.'s body.