Christchurch police say there could be more to a serious road rage incident after the alleged attacker came forward to tell his side of the story.
A 37-year-old man suffered serious facial injuries when he was allegedly attacked on Johns Rd in Harewood on January 6.
The man's 80-year-old father, who was the front-seat passenger, watched on as the incident unfolded.
The victim then managed to drive himself to hospital, where he underwent surgery before being discharged last week.
Detective Sergeant Mark Worner said a witness and the alleged offender had since come forward and were interviewed last night.