Police in Pennsylvania are trying to figure out who left a "significant" amount of cash inside a children's book donated to a library.

The Manheim Township Police Department said workers at the Manheim Township Public Library discovered the money hidden inside a copy of children's book Diary of a Wimpy Kid.

The book was donated Sept. 18, but the money wasn't discovered until later.

"Any person who makes a claim to the money will have to provide specific details as there are unique identifiers that only the true owner would know," police said.