Metropolitan Magistrate Navjeet Budhiraja extended the judicial custody of Shahrukh and Kartik till Sep 18.
The murder occurred Aug 5 in the crowded Madangir area of south Delhi and was caught on a CCTV camera installed outside a shop.
The footage showed Sachin, the 19-year-old victim, driving a bike with a pillion rider and running into the killers coming from the opposite direction. As Sachin and his friend fell from the motorcycle, the accused pounced on them. The pillion rider managed to flee.
Sachin tried to escape but was chased and pinned to the ground. The killers took him to a corner and stabbed him repeatedly on his back, chest and abdomen.
Three minors were also apprehended in the case and were later sent to a juvenile reformation home.
According to police sources, Sachin allegedly extorted money from the accused and beat them up over petty issues. The five accused told police they were fed up with his extortion and wanted to teach him a lesson.