Kenichi Philips was shot dead as he sat in a parked car in Ladywood in March.
Suspected Road Rage Attack In Birmingham
A father is critically ill after allegedly being punched during a suspected road rage attack in Birmingham
The assault took place on Gressel Lane in Kitt's Green, at 6.30pm on Friday.
West Midlands Police believe the incident occurred after the drivers of a van and a car got out of their vehicles following a minor collision.
The van driver is said to have punched the 37-year-old driver in what has been described as unprovoked attack.
He suffered serious head injuries and was taken to hospital, where he remained unconscious and in a critical condition, police said on Saturday.
The van driver left the scene before officers arrived.
Detective Constable Katie Lees, from Birmingham's violent crime team, said: ''This was a vicious attack on a family man who was on his way home to his partner and four-year-old child.
''The road is a really busy road and we are sure that there were lots of people who would have seen what happened and we are appealing for them to come forward.
''The victim phoned home as he left work - like he does every night - to say that he was on his way.
''His partner became worried when he did not arrive home and it must have been devastating for them to discover the news that he had been injured in such a random and vicious attack.
''I would also like to take the opportunity to appeal to the van driver to search his conscience and to do the right thing and to come forward. We have several lines of enquiry and it is only a matter of time before we come knocking at your door.''
Anyone with information is asked to call West Midlands Police on 101, or Crimestoppers anonymously on 0800 555 111.
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