Police said the woman has suffered 100 per cent burn injuries and is critical while the boy is yet to be traced.
Dattawadi police said Onkar Margale went missing from near his house on November 11.
A missing person complaint was registered at the police station on the same night by his father Bhausaheb Margale, a vegetable vendor.
Two days later, Margale registered a first information report at Dattwadi police station accusing his neighbour Zaibun Farid Shaikh, a chicken shop owner, of kidnapping Onkar.
Senior inspector Vijaysingh Gaikwad said, “Margale had lent Rs 40,000 to Shaikh and wanted the money back. He has alleged that she kidnapped his son because he was unable to give the money.”
Margale said, “Around 8 pm on November 11, I saw Onkar with her. She told me that she would buy crackers for him. He subsequently went missing. At first, we did not register a complaint against her. When we learnt that she too had been untraceable for some time that night, we registered the case. I have helped her financially earlier. We had also lent her a gold ornament.”
Gaikwad said, “She set herself on fire on Sunday using kerosene. Our teams are searching for the boy. Shaikh claims she does not know his whereabouts.”
Police said her statement has been recorded in presence of a magistrate.