Vandals attacked the construction site of a school which is undergoing a major renovation in Letterkenny.
The upgrade of Scoil Colmcille at Convent Road in the town has been ongoing since last year.
Gardai are now investigating a series of criminal damage incidents at the school between February 18th and 19th last.
A New Holland tractor being used on the site had a number of windows smashed on it.
Damage was caused to at least two portocabins on the site.
Gardai are anxious to locate whoever is behind these particularly mean attacks.
Anybody with any information is asked to contact Gardai in Letterkenny on 0749167100.