Chicago authorities have filed charges in the shocking murder of a pregnant woman whose baby was cut from her womb. Experts say such cases are rare, yet common enough to have a name: fetal abduction.

At a Thursday news conference, police announced first-degree murder charges against 46-year-old Clarisa Figueroa and her 24-year-old daughter, Desiree. Police said Marlen Ochoa-Lopez, 19, was heading to the Figueroa house after the mother posted an offer of free baby clothes on a Facebook chatroom.

They say that the daughter has confessed to helping her mother kill Ochoa-Lopez and that the mother’s boyfriend, 40-year-old Piotr Bobak, is charged with concealment of a homicide.

Police say the investigation is continuing but that Clarisa Figueroa’s adult son died of natural causes two years ago and they believe the woman was hoping to raise the newborn as her own.

Clarisa Figueroa called police hours after Ochoa-Lopez was killed to report that the baby had stopped breathing. The child that Clarisa Figueroa said was hers was rushed to a hospital where he remains in grave condition and is not expected to survive.

The case has similarities to many of the roughly 30 similar crimes carried out over the last three decades across the US, an expert said.

Of the roughly 30 documented fetal abduction cases between 1987 and 2015, most of the mothers were slain and it’s typical for them to have been stalked or lured somewhere under false pretenses including for free supplies, according to Kenna Quinet, an associate criminal justice professor at Indiana University-Purdue University Indianapolis.

Quinet said such cases were as illogical as they were horrific: she is unaware of any case in which the baby wasn’t found and the crime wasn’t discovered.

“Clearly, you’re not getting away with this,” she said. “These women are clearly delusional.”

The cases come along an average of once a year, with some gaps. It has even occurred before in Chicago, in 1995. That nearly full-term baby survived, but the mother, Debra Evans, and two of her other children were killed. Three people were convicted.

Quinet’s research shows that most babies survive, but far fewer of their mothers do. She found eight women who did, including one who escaped and killed the woman trying to kill her and take the baby.

Quinet said she could not find a definitive case before 1987. She said that correlates to a time in which hospitals boosted their security, significantly decreasing the number of newborns stolen from maternity wards or neo-natal units.

While fetal abduction endures, she said it’s important to note that it remains infrequent and shows no sign of increasing.

“If you consider an extremely rare event of the millions of women a year who are pregnant, there would be no way as individual people that we could take this risk to zero,” she said. “I think it’s as low as we can hope for it to be.”

