A 27-year-old security supervisor was bludgeoned to death by a guard at Koramangala Sony signal near Viveknagar in the wee hours of Friday.

Shivakumar — a native of Bihar, who was working as a supervisor at a private security firm — was returning home after his shift when he was attacked by his colleague, Sourab Roy (24), a guard with the same firm. Preliminary investigation revealed that Roy was being harassed by Shivakumar at work and the duo used to quarrel at workplace. They had a fight on Thursday evening, too, which would have resulted in the murder.

Police have arrested Sourab Roy. A senior police officer said the incident happened around 12.30 am when Shivakumar was returning home.