He added:
“The North Yorkshire Police do not tolerate these types of conduct.”
He encouraged anyone with information about the person in charge to come forward.
Fountains Abbey is one of two UNESCO World Heritage Sites in Yorkshire, the other being Saltier near Bradford.
The monastery's ruins are the largest in the country, dating back to 1132, when 32 monks left St. Mary's monastery in York and established a new community.
The monastery was disbanded by King Henry VIII in 1539, and the crown sold the property to the merchant, Sir Richard Gresham, before the crown was eventually handed over to the state trust.
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