LIMA, Peru — When the body of Claudina Herrera was discovered nearly five months ago by the side of a highway, curled in the fetal position in a cardboard box, the cause of death was obvious: The pregnant 18-year-old's belly was sliced wide open, and her baby was gone.

Within days, her premature girl was located in intensive care at a public hospital, and the woman who had shown up with the baby — covered in blood and saying she had given birth in a taxi — was arrested with four others.

Herrera's slaying to steal her unborn child has shocked Peru and served as an ugly reminder of the early 1990s, when widespread allegations of corrupt adoption procedures led to a crackdown.

It also suggests that an illegal industry is still booming: Dr. Luis Bromley, chief of forensic investigations at the Attorney General's office, said the alleged perpetrators belong to one of at least a dozen rings trafficking in babies in Peru.

Peruvian police, working with Interpol, the FBI and investigators from Spain, Colombia and elsewhere, say they already have broken one alleged ring.

Last month, a German man and his Peruvian wife were charged with selling a baby for $16,870 to a German woman, who was detained with the child in Ecuador.

Police think that for more than a year, the couple had been buying newborns from poor women, then bribing officials in isolated jungle towns to issue false birth certificates.

In the late 1980s and early 1990s, Peru was famous for its relatively quick, easy adoptions. Americans alone adopted more than 720 Peruvian babies in 1991.

That changed after a series of scandals in which children were allegedly kidnapped and lawyers and judges were bribed to fake paperwork.

An embarrassed Peruvian government created a National Adoptions Secretariat to enforce new codes so bureaucratic and time-consuming that the number of legal adoptions by foreigners plummeted to just 92 in 2004.

Activists say the restrictions may have merely pushed the industry underground.

Sandra Soria, executive director of Peru's nonprofit Institute for Infancy and the Family, said it is impossible to know how many children are sold each year, not only for adoption but also for forced labor and the sex trade.

Soria said Herrera's case was a classic example of how sophisticated rings infiltrate public-health clinics in search of vulnerable women. Bromley said that behind Herrera's case "there wouldn't be one, two or five people, but rather a mafia."

What set the case apart is that Herrera turned up dead. "No similar precedent exists for the death of Claudina Herrera," Bromley said. "These mafias don't function by murdering women to obtain babies."

Investigators believe Herrera's killers had an order to fill "and they urgently needed a baby girl," Bromley said.

An autopsy indicated Herrera had been hit on the head and burned on the chest — a sign that defibrillator paddles were used to try to resuscitate her, according to police reports obtained by The Associated Press.

According to police reports, Herrera was one of five pregnant teens approached in a clinic by Ysabel Palacios, the woman who registered as the baby's mother and is now charged in Herrera's slaying.

Palacios, 31, allegedly claimed to be a "coordinator" from Lima's prestigious Hogar de Madre birth clinic, and offered to enroll Herrera and the other girls, all in their final trimesters, in a free prenatal program for the needy.

Palacios told police the teens were confusing her with another woman who offered free medical care and promised to find "foreign godparents to provide help" once the babies were born.

She denied ever meeting Herrera and said she delivered her own baby girl in a taxi.

But a medical exam determined that Palacios had not given birth, and medical records showed that she had undergone tubal ligation.

When police confronted her with their evidence, Palacios admitted having called Herrera's house. But in a written statement to police, obtained by AP, she insisted that she was pregnant, and said she too was a victim of the ring.

Palacios told police she and Herrera were picked up by Diana Rivas, an obstetrics nurse, ostensibly for an appointment at the Hogar de Madre. Palacios claimed she went into labor in the taxi and began hemorrhaging, and that just before losing consciousness, she saw the driver strike Herrera on the head with a tire iron.

Palacios said she awoke and was handed a baby she believed was her own. DNA tests later revealed the baby to be Herrera's.

Rivas denied participating in Herrera's slaying but acknowledged preparing a history of prenatal checkups for Palacios.

Palacios is in jail along with four alleged accomplices: her boyfriend, ex-husband, Rivas and a clinic social worker.

The mother of Herrera's boyfriend, Pilar Villavicencio, is helping to raise the baby girl. They call her Fabiana Antonella — the name Herrera chose before she was killed.