Pregnant Chicago woman murdered, her baby cut from her body. Her family blames a Facebook post.

The last time anyone saw Marlen Ochoa-Lopez, she was nine months pregnant.

The petite 19-year-old left her alternative high school on the lower west side of Chicago at around 3 p.m. on April 23, driving away in her black Honda Civic. Later that day, her family got a call saying that she hadn't shown up to pick her 3-year-old son from day care. She had sent a text message to her husband saying that she was too tired to drive anymore, then vanished.

For nearly a month, as her due date came and went, her family desperately pleaded for her return, fearing that she had been kidnapped or worse. Her mother, Raquel Uriostegui, tearfully told reporters that Ochoa-Lopez's toddler was refusing to eat, and that they had had to take down all their family photos because he kept asking for her.

"She can't just have disappeared in thin air," Uriostegui said through an interpreter earlier this month. "She is a very responsible lady. She is not a person who just disappears and leaves home. I cannot believe that she would just leave, pregnant, and abandon her other son. There's something wrong here, something bad."

Any hopes that the teenager might still be alive were dashed on Wednesday, when officials confirmed that human remains discovered at a home on the southwest side of Chicago belonged to Ochoa-Lopez, and that her baby had been ripped from her womb.

Ochoa-Lopez was also known by the name Marlen Ochoa-Uriostegui. She died of ligature strangulation, which typically involves the use of a cord or rope, the Cook County medical examiner's office said, and her death was ruled a homicide. Anthony Guglielmi, the chief spokesman for the Chicago Police Department, told The Washington Post that her baby had been removed after she was killed.

Ochoa-Lopez's body was found hours after several people at the house were taken into custody for questioning, authorities said. Three remained in custody late Wednesday night, but no charges have been announced.

"It's as if this family lived through a horror film," Julie Contreras, a student pastor who spoke on the family's behalf, told the Chicago Sun-Times.

At around 6 p.m. on the same day that Ochoa-Lopez failed to pick up her son from day care, paramedics from the Chicago Fire Department were dispatched to the same southwest Chicago home where her body was found weeks later. The call was about a newborn baby.

"The caller gave birth 10 minutes ago," a 911 dispatcher says in audio recordings obtained by WLS. "46 years of age. The baby isn't breathing. The baby is pale and blue. They are doing CPR."

The infant was rushed to the hospital in critical condition, officials told local media outlets. According to Ochoa-Lopez's family, it was the missing teenager's baby, which had been cut from her body.

Relatives also told the paper that a few weeks ago, Ochoa-Lopez's Honda Civic was found abandoned a few blocks from the same house. It was covered with parking tickets.

While police haven't released any details about the ongoing investigation, family members have said that Ochoa-Lopez was lured to the home by a woman whom she met through a Facebook group for young mothers.

"She was giving clothes away, supposedly under the pretenses that her daughters had been given clothes and they had all these extra boy clothes," Cecilia Garcia, a spokeswoman for the family, told reporters at a Wednesday news conference. "That's the false pretenses that we believe led her to that house."

Screen shots obtained by CBS Chicago show that on March 6, Ochoa-Lopez posted a message to the now-defunct Facebook group, which was titled "Help a Sista Out." Her due date was approaching, she wrote, and there were still a lot of supplies that she needed.

"Due to the fact that I'm in school and can't work at the moment, I can't afford to buy the rest of the things since I'm short on cash right now," Ochoa-Lopez wrote.

The screen shots show that another group member responded, asking Ochoa-Lopez if she could wait a week. Her daughter had extra baby clothes that had never been worn, she claimed, explaining, "She was lucky to have two baby showers so she just loves to spread the wealth."

The woman said she was located near West 79th Street and South Pulaski Road, an intersection just blocks from the house where Ochoa-Lopez's body would later be found. She directed the pregnant teenager to message her privately.

By extracting DNA from Ochoa-Lopez's toothbrush and hairbrush, detectives were able to confirm a match with the infant who was rushed to the hospital in April, her family told the Chicago Tribune.

The baby, given the name Yadiel Yovany Lopez by the family, is on life support and has no brain function, family members said.

Speaking to reporters outside the medical examiner's office on Wednesday night, Ochoa-Lopez's husband, Yovany Lopez, wept.

"Why did these bad people do this?" he asked. "She did nothing to them. She was a good person."