New Delhi, Aug. 31 -- A 19-year-old man was stabbed to death and his cousin injured after four men allegedly attacked them with knives over an old dispute in south Delhi's Khirki Extension early Saturday, police said. The deceased was identified as Vivek Gupta, who worked as a helper at a restaurant in Select City Walk Mall. His cousin, Aman Gupta, 21, employed at another restaurant in the same mall, is undergoing treatment at AIIMS Trauma Centre. The incident occurred when the two were returning home late at night. Around 2 am, a PCR call alerted police after locals saw the cousins lying in a pool of blood on the street. At 2.25am, another call was received from Madan Mohan Malviya Hospital, stating that Vivek had succumbed to his injuries. According to Ankit Chauhan, DCP (South), CCTV footage showed the four accused armed with knives attacking the cousins. "The police team visited the spot. Raids are underway to apprehend the culprits," he said. Investigators said the accused and victims were known to each other and lived in the same area. "The accused had earlier threatened them after a fight. On the day of the incident, they followed the cousins, picked a quarrel and then stabbed them," a senior police officer said. Forty to fifty minutes after attacking the cousins, the accused committed armed robbery in the same area. At 2.53am, police received another call from Khirki Extension reporting that four men, with blood on their hands andcarrying knives, robbed a food delivery executive and fled with his bike. Relatives staged a protest outside the Malviya Nagar police station, accusing police of failing to act promptly. Vivek's mother, Devi Gupta, said, "They followed my son from the mall to the Khirki area. They had knives... What was his fault?... the police did not do anything." A senior officer denied allegations of inaction and said the accused had been identified and would be arrested soon....