Arsonists who tried to burn down a mosque last Saturday drilled a hole in the building and pumped in a flammable liquid, possibly petrol, the fire brigade said.
It is believed the attack, on the Sarum Hill mosque in Basingstoke, Hampshire, was made in response to the alleged airline bomb plot last week. The arsonists caused thousands of pounds of damage to delicate roof rafters, which were badly charred in the blaze.
Fire brigade sniffer dogs were sent around the mosque hunting for clues.
A Hampshire Fire and Rescue Service spokesman said: "The cause of the fire was malicious. It could be that more than one accelerant was used, or the dogs may have found evidence of the same fire-starter in different areas.
"No one got in to the building. It seems that they made a hole in the building and pushed the accelerant in."
The attack came despite increased police patrols in the area around the mosque, as authorities sought to reassure minority communities in the wake of the alleged terror plot.
Police are appealing to anyone with information to come forward, amid fears that the perpetrators may strike again.
A spokesman for Hampshire Police said officers had not made any arrests following the attack, which occurred at around 3.30am on Saturday.
"We're currently following up several lines of inquiry," he said.Reuse content