Nepal police on Thursday arrested a 25-year-old woman who allegedly beheaded her three-year-old nephew on the orders of a dark arts teacher.

The Nepalese woman, Mahadevi Yadav, was learning witchcraft and was told by the guru that her skills would only be complete after she sacrifices her nephew and her eldest son.

Police have arrested Yadav in the town of Samanpur, south of the country's capital Kathmandu on charges of "sacrificing" a child.

Police said that Yadav has confessed that she beheaded her three-year-old nephew, Nitesh Kumar Yadav, at midnight last Saturday (May 19).

Yadav told The New York Daily News that she was following her dark arts teacher's instructions and sacrificed the child. "I had been learning witchcraft from Chhabilal Yadav of Haraiya for the past month. He told me that my witchcraft skills would be complete only after the sacrifice of the nephew. Accordingly I took him at Bramhsthan and beheaded him on Saturday after a pooja," Yadav told the Post.

After beheading the boy, Yadav threw his head into the Bagmati River and buried the torso in her "pooja" room. Police have unearthed the body and have taken it to Gaur near the Nepal-India border for postmortem.

Yadav also said that Chhabilal later asked her to sacrifice her eldest son as well after her sacrificing nephew.

Her nephew Nitesh was a resident of Manpur and had been living with his maternal uncle's house for the past one month.

Earlier, Yadav registered a police complaint saying that the boy had gone missing. But later police got doubtful of Yadav's activities when she informed them that she found the boy's body.

Chhabilal and Yadav's family members are at large and Mahadevi is in the police custody, SP Thule Rai said.

According to villagers, Yadav was a normal woman and never had a history of any mental illness that they knew of.

The incident has shocked the local people and rights activists group in Samanpur.

"We are shocked to hear the news at a time when incidents of torture against women for allegedly practicing witchcraft are on the rise in the region," rights activists group member Bipin Gautam said.