The girl's body was found dumped in a garbage bin near a garden in Bainganwadi area in eastern Mumbai on Sunday morning. Her limbs were tied and there were strangulation marks on her neck and bruises on body, police said.
The victim, whose parents are labourers, had gone missing while playing outside her house on Saturday evening. Police suspect the minor was sexually assaulted before being killed.
"A man in his 30s, who stays in the same locality, has been detained and his role is strongly suspected in the crime. We are gathering evidence against him," said a senior police officer.
BJP MP Kirit Somaiya met senior police officials today and sought a speedy investigation into the case.