A Sri Lankan Tamil refugee was arrested on Friday on charges of sexually assaulting and impregnating a 32-year-old mentally challenged woman, residing in Malayandipattinam refugee camp near Coimbatore, police said.

The incident came to light when the victim's brother Vijayakumar, with whom she has been staying in the camp, noticed that she was vomiting frequently for the last one week following which he took her to a hospital.

The hospital authorities confirmed that the woman was pregnant, police said.

On questioning, she revealed that their relative Bhagyaraj had raped her, they added.

Vijaykumar and his wife had left the woman with Bhagyaraj before leaving for a pilgrimage a few months ago.

Following a complaint, Bhagyaraj was arrested and produced before a court, which remanded him to judicial custody, they added.