According to the police, Siddharath was the son of businessman Pradip Chaudhary and was studying in class IX in DPS School, Azadnagar.
The three accused-- Shubham, Jitin and Meghraj havwe been arrested.
He went missing on December 22 and his family members registered a complaint on December 23. On December 24 the kidnappers demanded Rs 20 lakh ransom, police said.
Based on Siddharath's mobile surveillance, police caught the accused from the IIT campus here. Jitin and Meghraj's fathers are fourth class employees at IIT and Shubham is a resident of Nankari area.
The accused who were known to Siddharath from last one and half years called him on Sunday and strangulated him to death.
They then demanded money from his father. The victim's body has been found in a lake near the Kalyanpur area and was sent for post mortem.