CHENNAI: A 16-year-old boy, a native of Bihar, was arrested on murder charges by the Egmore police after his 18-year-old co-worker, whom he attacked with a concrete dumbbell three days ago, succumbed to his injuries.

The deceased was identified as Rahul Kumar, also from Bihar. Both the teens were employed at a house on Montieth Lane in Egmore and stayed in separate quarters in the same compound.

On December 24, the teenagers had an argument which escalated into fisticuffs. In the melee, the younger teen took a makeshift dumbbell made of concrete and flung it at Rahul. Hearing the commotion, their employer rushed to their room, rescued the severely injured boy and moved him to the hospital.

On Thursday, Rahul succumbed without responding to treatment, after which the Egmore police who had registered an attempt to murder case altered the sections to murder and arrested the juvenile. He was produced before the Juvenile Justice Board and later sent to the government home for boys.