Imran Akhtar Hussain, 26, of Bracknell in Berkshire, is alleged to have punched a stranger in the face in Derby Road, on January 4.
But police face an investigation into the incident, after Hussain was charged with a murder in Manchester just 12 days later.
Notts police has referred its involvement in responding to the
incident in Nottingham to the Independent Police Complaints Commission,
which is investigating whether the force could have arrested Mr Hussain
before the alleged murder.