Officials at the force say they have referred themselves to the Independent Office for Police Conduct and the force's own Professional Standards Department due to "previous police contact with both parties". The incident happened at around 4.25am on Sunday on Rose Lane, when a BMW struck three people before leaving the scene. Following police enquiries, a 31-year-old man was arrested at around 11am the same day on suspicion of assault causing grievous bodily harm and drug driving. Both men were taken to Wymondham Police Investigation Centre for questioning and were later released on bail until September 2. The exact nature of the Independent Office for Police Conduct (IOPC) investigation is currently unknown.