A man who shot dead another traveller during what was meant to be a fair fight "broke every rule in the book", according to police.
36-year-old Jessie Smith was killed by Mark Mosley at a travellers' site in Burwell, Cambridgeshire, on New Year's Day.
Both familes had clashed on New Year's Eve and had planned to settle the dispute with a 'bare-knuckle fight'.
Click below to hear from Detective Inspector Alan Page
"From what I understand of the traveller culture, if you have an issue between two travellers, they have a bare-knuckle fight.
How did the murder unfold?
Jessie Smith's nephew Paul was assaulted by Mark Mosley during a party at the Comrades Club in Soham on New Year's Eve.
As is often the way in the traveller community, they agreed to arrange a bare-knuckle fight to sort out the disagreement.
In the early hours of New Year's Day, Paul and other members of the Smith family (including Jessie) made their way to the travellers' site in First Drove, Burwell, where Mr Mosley lived.
It was as the fight was taking place that things took a turn for the worse.
Mosley grabbed a sawn-off shotgun and shot Jessie Smith three times.
The fatal blow was one to his back as he was trying to get back into his vehicle to escape.
Another relative (Albert) was also shot in the hand while Mr Mosley pointed the gun at Paul and pulled the trigger, but it didn't fire.