An unidentified vandal has been leaving a mark on the Leamington library.

For the third time in as many weeks, staff at the John Street building have found urine on books and shelves in the fiction section.

“This is very unusual behaviour. In all the years I’ve worked in libraries, I’ve never heard of this happening,” said Janet Woodbridge, chief librarian of the Essex County Library system.

Woodbridge estimates about $3,000 worth of books have been damaged.

“It’s vandalizing a public asset that the public has paid for,” she said. “They’re hurting themselves and everyone else in the community because the material is no longer available.”

Staff at the library are co-operating with the Leamington OPP, and have taken steps to curb the vandalism, including patrolling the branch more often and installing a security mirror.

Woodbridge is asking library patrons to be vigilant and to report any suspicious behaviour to branch staff.