A Florida mother charged with the heinous murders of her two children may now face an additional murder charge after her third child, a five-month-old boy, died Sunday. 

Christopher Swist was taken off life support Sunday night following the Friday attack at his mother's home in Palm Bay that left his 7-year-old sister Laci McCarty and his 6-year-old brother Philip McCarty dead, Florida Today reported.

Initial reports of the incident stated 33-year-old Jessica Lacey McCarty stabbed her children. But autopsies performed Sunday revealed the two eldest children were strangled. The 7-year-old was also drowned and the mother is believed to have strangled the 5-month-old.

Jessica McCarty is currently on suicide watch at Brevard County Detention Center, where she was ordered held without bond on two murder charges after waving her right to her first court appearance on Sunday.

Investigators say McCarty called 911 at around 6 p.m. Friday stating she killed her children and had slit her wrists. McCarty's boyfriend, Christopher's father, also called authorities after police say McCarty sent him bloody photos of the alleged crime scene throughout her house. 

Officers arrived at McCarty's residence to find her holding a knife and her two children unresponsive with lacerations. Her boyfriend also arrived and found his son unresponsive with a cord around his neck, Florida Today reported. Laci and Philip were pronounced dead at local hospitals.

Police ordered the mother to drop the knife and struck her with beanbag rounds when she did not comply, Reuters reported.

As of Tuesday, investigators are still trying to piece together why McCarty allegedly killed her children. The Department of Children and Families had contact with the mother in 2009 for alleged "inadequate supervision." It also appears she had a history of drug abuse and was having trouble with her boyfriend. 

"Indications are that there were some issues with their relationship," Palm Bay Police Chief Mark Renkens told the newspaper.

"We do have leads," the chief continued. "My understanding is that she made some utterances. But there's nothing at this point that would have led us to believe she would have done what she did."