Nick Routledge was landscaping his garden in Ancaster, Lincolnshire, when he found human remains.
Police advised motorists to find alternative routes after the incident near Sleaford Golf Club.
Police say the incident involved victims having catapults fired at them after being surrounded.
The group also rammed a farmer's vehicle in a "terrifying" incident in Wiltshire, police said.
A smoke plume could be seen for miles around during the fire on Saturday.
