Carlos Rivera, 30, and Carmen Ramirez, 27, both of the 7300 block of Sommers Road were charged in connection with the death of little Nathalyz Rivera.
In addition to the murder charge, Rivera and Ramirez have also been charged with involuntary manslaughter, endangering the welfare of a child and criminal conspiracy.
Both Rivera and Ramirez were arraigned on Tuesday and were ordered to be held without bail.
"This is one of the worst cases of abuse that I've seen in my five years on the homicide unit. Very sad and very disturbing," Philadelphia Police Homicide Captain James Clark said during a press conference Monday afternoon.
Rivera found Nathalyz unconscious inside their Sommers Road home around midnight Monday.
"Instead of calling police or the ambulance, he called the mother who was over at a male friend's house," Clark said.
After arriving home, police say Carmen Ramirez and her male friend took Nathalyz to Albert Einstein Medical Center where she was pronounced dead at approximately 1:50 a.m.
Clark said Nathalyz showed "obvious signs of neglect." The medical examiner ruled her death a homicide through starvation.
According to Clark, the house was in such bad shape that Nathalyz appeared to have suffered bruises from either fleas, rodents, or insects biting her.
The child had special needs and, police say, the mother told detectives the girl suffered from Down syndrome.
Sources say the Philadelphia Department of Human Services had contact with the Rivera family in 2008, shortly after they had moved to Philadelphia from Chester County.
The other Rivera children - ages 9, 8 and 7, along with Nathalyz's 3-year-old twin - were being checked at a hospital before being placed with the Department of Human Services.
Neighbors say it seemed the couple was overwhelmed caring for the children, who were often unkempt.
"Dirty, very thin, pretty kids, very pretty," neighbor Annetta Dangerfield
"I think it's sad that people have children and allegedly don't want to take care of them," neighbor Furman Pace said.
"It bothers you when you hear something like this, especially in your neighborhood," said Valencia Barnes. "It's so close to your home. Makes you wonder what else you could have done."
"I think it's a shame that this baby is gone, that this baby wasn't fed or taken care of," said neighbor Betty Enoch.
As this investigation continues, anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.