Police are investigating possible sabotage at a historic flaming barrel-carrying event in Devon in which two people suffered serious burns.
The tradition of carrying tar barrels which have been set alight through Ottery St Mary has taken place on November 5 for centuries.
Last Thursday, one of the barrels exploded, causing serious facial burns to one man while a second man suffered burns to his hand.
Devon and Cornwall Police said they were investigating reports that an aerosol was put into one of the barrels, causing the explosion.
Both men were treated at Bristol's Frenchay Hospital, but have now been released.
A police spokesman said: "Officers believe other spectators may have also suffered minor burns and are keen for them to come forward and speak to the police.
"It is thought some of those injured are not from the local area and travelled from Avon and Somerset and from further afield.
"The area was obviously very busy with spectators throughout the night and police would like to hear from anyone who witnessed the incident, or has any information, to call the police on 08452 777444."
The exact origins of the tar barrels event are unknown but it was probably started after the gunpowder plot of 1605. It takes place at the Ottery carnival after a procession of tableaux and a firework display.
The bonfire is then lit before tar barrels are set on fire and carried through the streets. The "barrel rollers" come from generations of families who have lived in the town.