The mystery over the fate of a 19-year-old pregnant Chicago teen missing for the past three weeks took a dark turn on Wednesday when authorities announced she’d been found slain, with her baby cut out of her womb, and stuffed into a garbage can in the yard of a woman who’d allegedly offered her free baby clothes online.

The baby of Marlen Ochoa-Uriostegui is said to be in critical condition at a local hospital after being passed off as the 46-year-old woman's child late last month, immediately after the teenager was reported missing at nine months pregnant. The Cook County Medical Examiner determined the expectant mother's cause of death to be “ligature strangulation” and ruled her death a homicide on Wednesday.

Sources cited by the Chicago Sun-Times say the unidentified 46-year-old woman is expected to face charges. Ochoa-Uriostegui's family told local media the mother-to-be had met the woman in a Facebook group and went to her home after being offered baby clothes for her unborn son.

“She was giving clothes away, supposedly under the pretenses that her daughters had been given clothes and they had all these extra boy clothes, and that's where the false pretenses that I believe led her to that house,” Cecilia Garcia, a spokesperson for the teen’s family, told ABC 7.

Shortly after the teenager was last seen on April 23, an older woman was seen covered in blood and holding a baby in a towel outside the home where the 46-year-old woman lived, screaming that her baby needed help and wasn't breathing, neighbors told ABC 7.

The Chicago Fire Department responded to a 911 call at the home that same night after a 46-year-old woman called and said she had just given birth and the baby was “pale and blue.”

The baby, who has been in the hospital since April 23, has now been identified as Ochoa-Uriostegui's child after a DNA test, her family said Wednesday.

The baby’s father and Ochoa-Uriostegui’s husband, 20-year-old Yiovanni Lopez, reportedly visited the child Tuesday night and named the baby Yadiel Yiovanni Lopez. Garcia, the family spokeswoman, said the baby was in “critical condition.”

Police have not yet announced charges against the unnamed 46-year-old woman, but Anthony Guglielmi, spokesman for the Chicago Police Department, was quoted by the Sun-Times saying that four “persons of interest” were in custody in connection with both Ochoa-Uriostegui's death and the “incident involving the baby.”

Police were reportedly led to the woman by an anonymous tip after she set up a GoFundMe campaign seeking $9,000 for her baby's funeral, saying he was very ill and about to die.

A woman who said the 46-year-old used to babysit her baby told ABC 7 she had begun to exhibit strange behavior recently. “She told me how she was getting really attached to the baby, how she couldn't wait to be a mom again,” the woman, who asked not to be named, told the news outlet.

A neighbor of the woman also told the Sun-Times about seeing her on her porch with the baby as an ambulance arrived on April 23. “She said, ‘I stood up and the baby came out,’” the neighbor was quoted as saying. “Before she left in an ambulance, she told me several times, ‘Please call up someone to come and lock the house.’”