The abbey was built by order of King David 1 about 1140
Vandals who unearthed and damaged ancient stones at a medieval abbey near Stirling are being hunted by police.
Central Scotland Police said those responsible broke an historic moulded stone at Cambuskenneth Abbey and moved others housed in the bell tower.
The damage was caused sometime between 0930 GMT and 1830 GMT on 27 March and was uncovered by a caretaker.
The ancient monument, built circa 1140 on the orders of King David I, was then targeted again by vandals on 3 April.
Chief Insp Kevin Findlater, appealed to the owner of a white minibus who may have been in the area at the time to come forward.
He said: "This type of behaviour will not be tolerated.
"This is a site of historic interest and I urge the public to come forward with any information they may have about these incidents.
"I am particularly interested to speak to anybody who may have been on a white minibus which parked in the area on Thursday March 27."
The chief inspector said patrols in the area had been stepped up.