Police discovered more than 1,000 litres of stolen fuel after arresting five people.
Nottinghamshire Police were called to Clumber Road in West Bridgford, Nottingham, at about 22:15 GMT on Friday after men were seen moving barrels from one vehicle to another.
Four men and a boy, aged 13, were arrested on suspicion of fuel theft.
More than 1,000 litres of fuel and siphoning equipment were later recovered from an address in Radford.
All five people have been released under investigation, Nottinghamshire Police said.