Metropolitan Magistrate Deepak Wason sent 21-year-old Sarna's friends Shivang Gambhir, 20, and Madhav, 20, to police custody.
The remaining four arrested accused -- Pranil Shah, Rythm Girhotra, Surender Bali and Naresh Mishra - were sent to judicial custody till Sep 30 after the police said they were not required for interrogation.
According to police, Pranil and Rythm are friends of Sarna while Bali and Mishra were security guards at the apartments in south Delhi where the incident took place Sep 13.
Sarna, who had completed his high school from New York, was to return to Canada for further studies but died after a drug party Sep 13 night organised at his friend's flat at South Park Apartment in Kalkaji area.
Police said the party lasted till midnight after which Sarna was thrashed by the guards for creating a ruckus in the complex. Around 2 a.m. Sarna's body was found bleeding in the apartment complex body. He died in hospital.
Investigators said the two guards were arrested for assaulting Sarna, while the NRI's four friends were taken into custody for drug abuse.
Seeking two days' custody for Shivang and Madhav, police said the investigation is at an initial stage.
The chain of the events needed to be built to find out why the two went to Pranil's flat and consumed drugs, police said.
"We have seized electronic data from the spot, which has to be probed thoroughly as it may give us the clue about the flow of drugs into India through illegal channel, in which the accused were involved," police said in an application.
--IANS (Posted on 17-09-2013)