LIMA (Reuters) - One woman has been killed and some 40 people were arrested in a Peruvian shantytown after an angry mob tried to lynch two pollsters whom residents believed were butchering local children to take their organs, authorities said Friday.

False rumors on social media claiming dead children had been found with their organs missing fanned mass hysteria in the shantytown Huaycan on the outskirts of Lima, prompting residents to target two employees of a polling company who had been conducting door-to-door marketing surveys, said Police General Hugo Begazo.

“From one second to the next, people started to surround us,” said visibly shaken Luis Nunez with polling firm Quantum in broadcast comments. “They nearly lynched us and set us on fire.”

Police managed to pry Nunez and his colleague from the mob, which then attacked the police station in Huaycan where they were being held for their protection, Begazo said.

Police are investigating the death of a Huaycan woman who died from a bullet wound following the unrest late on Thursday, Begazo said.

Footage of the clashes showed police launching tear gas at a crowd and firing bullets in the air as people ran screaming and men threw rocks.

Begazo said more than a dozen police were injured and that Molotov cocktails were thrown and cars set on fire.

The clashes in Huaycan underscore the deep mistrust that often exists between authorities and residents of poverty-stricken areas across Peru where policing is scant and residents regularly band together to fight crime.

Peruvian Interior Minister Carlos Basombrio called the organ trafficking rumors “irresponsible” and designed to instill fear.

“Those spreading this information will pay the consequences,” Basombrio said, without offering specifics.

One Facebook post warned Huaycan residents, many of whom are migrants from the Peruvian highlands, to keep their children safe after the arrival of “pishtacos,” a monster in Andean folklore known for killing people to extract their fat.

Other posts said the bodies of children were turning up without eyes or other organs, and with cash or thank you notes left behind.

After the polling workers were cornered, someone used a megaphone to summon residents to help punish them, said Nunez.

The woman killed was a mother who collected discarded recyclable materials for a living and was not a part of the mob, her neighbors told TV journalists.

In 2009, Peruvian police said a group of “pishtacos” were killing people to sell their fat for cosmetics - a claim they later admitted was false.