PHILADELPHIA (AP) -- A severely disabled 3-year-old girl who weighed just 11 pounds when she died Monday was starved to death, Philadelphia police said as they held the girl's parents for questioning. Nathalyz Rivera's father found her unresponsive inside the family's bug-infested home around midnight, but called her mother instead of 911, Homicide Capt. James Clark said. The girl was driven to a hospital where she was pronounced dead. Carlos Rivera, 30, allegedly fled after dropping off his four other children with a relative but was found later in the day and detained at police headquarters, where his wife was also being questioned. "It's very sad, very disturbing," Clark said of the girl's death, which the medical examiner termed a homicide caused primarily by starvation. Nathalyz also had some bruising, but Clark said that may have come from flea, bug or rodent bites at the house, which he said was in "bad shape." "(She) had not seen a doctor in over a year, even with all the severe disabilities," Clark said. He did not specify the girl's medical conditions. Police have handled several starvation deaths involving children in Philadelphia, including the 2006 death of a disabled teenager whose family was targeted for an array of weekly city services at their home. Danieal Kelly weighed just 42 pounds when she died at age 14. More than a dozen people were convicted in the case, including her parents, city social workers and contractors. Nathalyz, a twin, was not in preschool or enrolled in any other city services despite her special needs, Clark said. The family had one prior contact with the Department of Human Services in 2008, but Clark did not immediately view that issue as relevant to the girl's death. Her mother, who is married to Rivera but apparently comes and goes at the house, was being interviewed by police Monday afternoon. Clark said she had seen her daughter in recent weeks, and he expected her to be charged in the death. "I saw the photos and even for me, they were difficult to look at," Clark said. 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 DHS. Danieal Kelly's death became the subject of a harrowing grand jury report, which found that city workers and contractors lied about making the visits to the family home. They are now serving lengthy prison terms. The girl's mother is serving 20 to 40 years for third-degree murder, and the father up to five years for felony child neglect, for abandoning Danieal at her unfit mother's home. In a more recent case, a homeless mother of six was convicted of involuntary murder this year for the starvation death of her premature twin at a shelter just before Christmas in 2010. Quasir Alexander, who was 2 months old and weighed just over 4 pounds, had been seen by a social worker shortly before his death. The social worker testified that she had not seen the twins undressed. Quasir's twin was found near death. The mother, Tanya Williams, awaits sentencing. Her defense lawyer has questioned how much she understood about caring for the premature infants, given her low IQ. The twins were released from a city hospital to the homeless shelter when they were four days old, although Williams was getting parenting help there from several sources.