Accompanied by her three children, the woman went to a police station in the Sidhi district of Madhya Pradesh in central India, where she told officers her brother-in-law had raped her, the Times of India reported.
Police attempted to send medical support to the man, but he was found to have committed suicide.
His body was reportedly found hanging from a tree near their house.
The woman had been living with her brother-in-law because her husband worked more than 700 miles away, in Nashik, Maharashtra.
She reportedly told police that she had used a sickle to cut off her brother-in-law’s penis as it was the only way to stop him attacking her.