Eighteen severed body parts, including two headless torsos and limbs, were found in a river under a bridge in western Bihar's Kaimur district on Sunday.
Locals spotted two torsos floating in the water and two blue suitcases with severed limbs and body parts.
A child, believed to be 10-12 years old, is believed to be one of the two victims.
Police said the suitcases possibly opened when they were thrown into the Durgawati River.
Senior district police officers and forensic teams were deployed to assist with the investigation.
The police officer said the manner in which the bodies were dismembered and dumped made it clear that this was a premeditated crime.
