The incident took place on August 11 when the four accused allegedly stabbed to death 28-year-old Amit in the Dakshinpuri area of south-east Delhi.
"Gaurav, Nitin and Mahesh along with a juvenile were involved in the crime. All four have been arrested," said Deputy Commissioner of Police (South East), P Karunakaran.
According to police, there was intense rivalry between two groups of anti-social elements operating in the area and they would be involved in frequent clashes.
A case in the matter has been registered at Ambedkar Nagar police station. The juvenile has been sent to an observation home, police said, adding that the three accused are in police custody.