The accused was identified as Dhruv (18) who was aided by his 21-year-old sister and their 40-year-old mother, all residents of Daryapur Kalan, Delhi.
The accused claimed they adopted a modus operandi for the crime which they saw in an episode of a crime TV serial.
DCP (outer north) Gaurav Sharma said that police received a complaint about a three-year-old boy missing from his house since 11.50 a.m. on Sunday.
During investigation, at about 5.30 p.m., while examining the CCTV footage, a suspicious movement of a commercial vehicle was observed. It was found that Dhruv owns the vehicle and lives in a rented colony but was shifting to a new address and on the day of incident the victim and two other children were offered fruit drinks by Dhruv.
During interrogation, Dhruv confessed to kidnapping for ransom with the help of his mother and sister and told the police that they shifted the boy to their new rented house at village Daryapur, from where the victim was rescued and the accused's mother and sister were also nabbed, police said.
"Dhruv further disclosed that he had recorded his voice by changing the pitch for sending the same for extortion demand through WhatsApp. He learned the modus operandi through an episode of a crime serial," said Sharma.
Police said the accused hatched the conspiracy as Dhruv's elder sister's marriage had been fixed but due to a lack of money it had to be annulled. He was in need of money so he planned to kidnap the son of his neighbour who used to deal in sale and purchases of used cars, also owns an Audi car and all his family members have iPhones.
( With inputs from IANS )