The boy was rescued after an encounter between the police and the kidnappers on February 6 at Shalimar City in Ghaziabad's Sahibabad area.
Of the four accused, Ravi (25) was killed in the encounter, while Pankaj was arrested. Nitin Sharma, another accused, was arrested on February 6, and Anshul Malhotra, his accomplice, after the boy was rescued.
They had demanded a ransom of Rs 60 lakh for the child's release, according to the charge sheet.
Nitin used to make the ransom calls in the voice of a woman to mislead investigators, police said.
The charge sheet was filed before Chief Metropolitan Magistrate Ajay Garg in the Karkardooma Court earlier this month and the accused were booked for kidnapping, attempt to murder, theft, wrongful restraint and under provisions of the Arms Act.
The charge sheet mentions that Malhotra, who happens to be a friend of Nitin, had supplied arms to them.
The 43-page charge sheet lists 81 witnesses and the evidence include stolen mobile phones that were used by the accused to make the ransom calls and send a Whatsapp video of the boy saying "I love you" to his father.
Other evidence include footage taken from CCTV cameras on the route from where the boy was kidnapped.
The charge sheet also mentions that Nitin used to make ransom calls in the voice of a female to create an impression that a woman had planned the entire episode and throw the police off-track.
Nitin's voice samples have been sent for forensic examination and a report is awaited, it said.
Vihaan Gupta, the son of a wholesale businessman, was kidnapped by Nitin who knew that his father had recently struck a business deal of Rs 37 lakh, police said.
The accused had decided to kidnap the boy to make quick money, they said.
The case was transferred to the Crime Branch on January 28 on the instructions of the Commissioner of Police.
Nitin was arrested from Seemapuri on February 5 when he was returning from a marriage party, the charge sheet stated.
The police were keeping a tab on his movements and had even entered the wedding venue posing as guests, it said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)