On July 15, police and paramedics were called to Rivero's home at 8:25 a.m. to respond to a report of a baby in respiratory distress. They found Niccolo Varner unresponsive. He was taken to Mercy Fitzgerald Hospital and pronounced dead.
"Unfortunately, this child died long before he got to the hospital," said District Attorney Jack Whelan.
Rivero was detained by police for possession of drug paraphernalia and questioned about the circumstances of the child's death, according to a police report.
Rivero said that she put the infant in a tub with his 5-year-old brother around 11 p.m. and never left the room.
A week later, however, Rivero gave police a different account, according to court documents. She said she left the boys in the bathtub and went to the backyard to snort heroin. Her older son called to her to say Niccolo had fallen and had struck his head. Rivero returned, dried off the baby, kept him awake for 45 minutes to watch for signs of a concussion and eventually put him in his pack-and-play crib to sleep. The next morning, she said, she discovered the baby unresponsive.
Victor Varner, Rivera's fiance and the boy's father, who was living with her at the time, told officials Rivero used heroin during her pregnancy. The baby was born addicted and spent two to three months in the hospital after his birth.
Varner said that he suspected Rivero was using heroin again but that she denied it when he confronted her. He told police that he hid his diabetic needles so she could not find them and that he slept with his wallet because she had stolen it in the past, according to the court documents.
On Tuesday, after receiving toxicology results, the medical examiner determined that the baby died of acute heroin intoxication.
"This child was given or consumed heroin," said Whelan. He said that he did not know how the baby received the drug but that the drug had not been ingested through breastfeeding.
The older child has been placed in the custody of the father, Whelan said. Rivero recently was living in Sharon Hill with her mother.
Rivero, who is originally from Bristol Township, Bucks County, was taken into custody Thursday night, Whelan said. She has a previous criminal record for receiving stolen property and was arrested on Oct. 27 in Sharon Hill for driving under the influence, he said.
A preliminary hearing is set for Tuesday, Davis said.
Contact staff writer Mari A. Schaefer at 610-892-9149, firstname.lastname@example.org or @MariSchaefer on Twitter.