Police also conducted a raid at the Malviya Nagar residence of the accused, Pulkit Sanwal, and seized his laptop.
All three were under the influence of alcohol and they work as drivers.
In Lajpat Nagar, the multicultural neighbourhood where Nido Taniam was assaulted, communities coexist in a very Delhi kind of compromise
Singh asserted that all people from the northeast and other parts of the country have every right to work and live in peace in the capital.
Three persons were arrested in the case and are presently in judicial custody till February 18.
Northeast youngsters protested at Lajpat Nagar saying they wanted justice Arunachal Pradesh student Nido Taniam.
Sources said Rajesh was the one who was passing on information to the gang members. Rajesh has been planning this robbery for the past three months.
The death evoked strong reactions from other groups in his home state as well as across the Northeastern region.
Relatives claim that the boy had an altercation with some shopkeepers after they made fun of his hairstyle.
Kejriwal said that there was no place for elements trying to spread hatred against people belonging to any particular part of the country.
A day before the robbery, Kalra had spoken to a Dubai number for around 20 minutes, police sources said.
Police is checking the CCTV footage of the area to identify the culprits.
The officer said Rastogi was headed towards Lajpat Nagar from the Modi Mill flyover in Okhla at the time of the incident.
The case was registered by the CBI under various sections of the Indian Penal Code and Prevention of Corruption Act.
A day after an Iranian woman filed a complaint of robbery claiming that she had been assaulted and robbed of Rs 6 lakh-worth of gold jewellery by an auto-rickshaw driver and his associate.