Merseyside police are investigating repeated thefts of large amounts of lead from the roof of Liverpool's Princes Road Synagogue.
Thousands of pounds' worth of damage is thought to have been caused to the Grade I-listed building.
The latest theft comes after £170,000 worth of repairs to Princes Road, funded by English Heritage and communal donations. The robbery has also caused rainwater to leak into the shul's annexe, causing further damage.
Police were first alerted on Monday morning after significant amounts of lead were seen to be missing. Representatives of a security company which patrols the building reported a second incident when thieves returned on Tuesday night. Adolescents were seen collecting lead which had been thrown to the ground.
The synagogue's senior warden, Laurence Goldman, said he was unsure who would pay for the damage.
He said: "I'm not sure we have that money spare, so I am hoping it will be covered by the insurers. I understand there may be a meeting between the insurers and our architects. It is very frustrating as it is difficult to know what we can do.
"We have been in touch with police to minimise the risk of thieves doing it again."
A spokesperson for Merseyside police confirmed officers were investigating and had taken a statement saying lead from the whole length of the roof was missing.
An official at English Heritage said the organisation was "disappointed to learn about the theft of lead from the roof of Princes Road Synagogue as it is such an integral part of keeping the building weatherproof.
"The theft is a symptom of a much wider problem that places of worship face across the country and we will be working with the synagogue to advise them on the steps they can take to repair the roof."