The woman, who is said to have owned up to the crime when a neighbour saw her with blood stains on her face, has been arrested and sent in 14 days of jail custody.

Neighbours told the police Anjana Maity (42) seemed depressed after his husband Ranjit Maity deserted her for some other woman.

“We were informed about the incident by her landlord. The boy was beheaded after he was castrated. We have sent the body for postmortem. Anjana confessed she had killed her son as she was deserted by her husband,” said an investigating officer.

After being booked for murder at the Thakurpukur police station, Anjana was produced before Alipore court, which sent her in 14 days of jail custody.

According to a police officer, Ranjit Maity (44), the boy’s father, was not present at his home when the incident took place. Ranjit reached the house after being informed of the murder.

“The woman may be having a psychological disorder. However, it has not yet been ascertained,” said South 24-Parganas SP L N Meena.

Bapi Mazumdar, the landlord of the house where the Maity family lived in a rented room, was the first to spot Somnath lying in a pool of blood.

“Around 6 am, when my mother came downstairs to open the main gate of the house, she found Anjana sitting at his doorsteps with stains of blood on her face. When she asked what had happened, Anjana said she had killed her son. My mother immediately informed me. I entered the room to find Somnath’s body covered with a blanket and he was lying in a pool of blood,” said Bapi, adding Anjana was sitting there with her hand bag.

Later, the police recovered some of her jewellery from the bag and the blood-stained scythe used to kill Somnath. Tapas Manna, a neighbour, said that the woman, along with her son, had been living there for the past 22 months but were not social. Ranjit, an employee of a private courier service, used to stay elsewhere. The boy was a Class VIII student of local Swami Premananda School and was brilliant. “We do not have any knowledge about any kind of problem the family was facing. Apparently, it was a happy family. Somnath used to stand first in his class. Anjana, along with her son, came back last night after spending two days in their native place at Chanditala in East Midnapore,” said Manna.