A 41-year-old man, Bheemesh Babu from Karnataka's Chitradurga, was allegedly killed by his co-worker after a quarrel over switching off a light at their rented office in Bengaluru, police said. They added that the accused, 24-year-old Somala Vamshi from Vijayawada, hit Bheemesh on the forehead with a dumbbell, killing him on the spot, and later surrendered at the police station.