A man hailing from Manipur allegedly stabbed to death a 65-year-old security guard in south Delhi's Safdarjung Enclave after mistaking him as the auto-rickshaw driver he had an altercation with, police said on Wednesday.

Ram Bahadur was attacked while he was resting in an auto-rickshaw on the intervening night of Tuesday and Wednesday, they added. Bahadur, who was employed as a watchman in a colony in Safdarjung Enclave, was rushed to the AIIMS Trauma Centre where he later succumbed to his injures, police said.