Three-year-old Jerusha Santhyakumar went missing while waiting for her mother by an irrigation channel.
Civil society activists have accused police of failing to take the disappearance seriously and have called for intensified efforts to find the child.
Campaigners against sexual and gender-based violence report that Jerusha's mother, Selestina, was violently assaulted by the police while trying to file a complaint, allegedly for having been married three times.