Two days ago, Prema handed over the boy to the father of her husband, who died in 2012. The grandfather, Murugesan, found a number of burn injuries on the body of the child.
Murugesan of Mullaivadi lodged a complaint with police which arrested Prema under various IPC sections and produced her before a court in Attur.
She was remanded to judicial custody for 15 days, police said.