The decomposed bodies of two siblings abducted from outside their east Delhi school four days ago were found dumped on a railway track in central Delhi's Pragati Maidan on Saturday morning.
Mansij, 7, and his sister Yashvi Kumar, 5, seemed to have been murdered hours after being abducted from Mother Convent private school, near their home in Mandawali, on Tuesday.
An autopsy report said there were fatal injuries on their throats and their limbs had been chewed on by animals.
They were identified by their uniforms after a passerby spotted them on the tracks near Pragati Maidan power station around 9.30am.
Police said the abductors were two motorcycle-borne men known to the children. Several ransom calls demanding Rs. 30 lakh were allegedly received by their father Manoj, a sales executive for a share brokerage firm, and mother Yogita, a homemaker.
A letter was also found in an autorickshaw parked at the end of the street where their home is located.
The first ransom call was made around 6pm Tuesday. Subsequent calls were later traced to three different PCO booths within a kilometre of their house - leading police to suspect the involvement of insiders.
Responding to the calls, the family reached two locations, including the Sarai Kale Khan bus stop on Wednesday evening, with the ransom amount where they met two men who directed them to Kalkaji - but to no avail.
"I had arranged around Rs. 25 lakh and sent Manoj to get the children, but nothing happened. The next day, they called Yogita to a school near their house and, over the phone, claimed the children were being kept in Noida and would be released in two hours," said Vijay Pal, the children's grandfather.
"We arrested some suspects and believe the incident might have been triggered by personal enmity," a police officer said.
The suspects include Vivek, the son of the family's landlord with whom Manoj recently had a tiff, a local cable operator, and one of Yogita's relatives, who has a criminal history.