The police arrested Allen (21) of Devanesan Nagar in Peerkankaranai, an AC mechanic in connection with the murder. The deceased, Aaron, who worked as a driver at the Chennai corporation, was an alcohol addict and would often beat his wife after getting drunk. Despite Allen’s repeated warnings, on Tuesday night when Aaron picked up a quarrel with his wife again, Allen tried to intervene. But his father came at him with a log. Allen then snatched it and hit Aaron on the head with it. He fell and lost consciousness and was rushed to Chromepet government hospital where he succumbed on Wednesday morning.