Someone is soaking books in urine at a southwestern Ontario library.

Staff at the Essex County Library branch in Leamington, Ont., says more than 300 books have been ruined by urine, costing more than $3,000 in damage.

Library CEO Janet Woodbridge said that staff has discovered stacks of urine-soaked books on at least four occasions in the last three weeks.

"A staff member was looking for a book for someone and that’s when they realized the books were damaged," Woodbridge said.

Woodbridge said the frequency is "escalating."

The books were found out of staff sight in what Woodbridge called "an area not often frequented by the public."

The books have been removed from circulation.

"We would never circulate such items to the public again," Woodbridge said.

Staff members are now patrolling the library every 15 minutes in an effort to catch the culprit.

Woodbridge said cameras will also be reluctantly installed.

"We have never had a need in our libraries to have cameras. We don’t want our libraries to look like a police state," she said. Woodbridge said she has no idea who covering the books in urine, nor why.

"We’ve had things tossed in book drops but nothing like this," she said. "They don’t appear to be making any editorial comment."