Two youth were chased down and stabbed to death by an unidentified gang in the Avadi and Pattabiram police station limits on Saturday. The police identified the victims as Rettamalai, 27, and his brother Stalin, 24, of Aayili Cheri, who have a criminal case against them in the Pattabiram police station limits. The duo, while drunk, had allegedly quarrelled with the gang, who attacked them with knives in retaliation. Avadi City Police Commissioner K. Shankar formed a special team to trace the suspects. Further investigation is on.