SEATTLE — A Seattle non-profit group that provides free used books to Washington prisoners said it was recently caught off guard by an abrupt decision to ban those books from getting to prisoners.

“We couldn't figure out what was going on because we've been sending for over 45 years,” said Michelle Dillon, a volunteer and board member with Books to Prisoners.

For decades, the organization has been sending used novels, non-fiction volumes, magazines, and their most-requested books, dictionaries, to inmates across the country.

Inmates write letters to Books to Prisoners with requests, and volunteers send back bundles of reading materials.

But recently, prisons in the Washington State Department of Corrections started sending those book packages back.

“It was written on the outside of the package, ‘no used books, not authorized,’” said Andy Chan, Books to Prisoners secretary.

Books to Prisoners investigated and found a letter buried on the DOC website, quietly announcing a ban on used books sent by non-profits.

The letter notes that DOC mail rooms don't have the resources to review incoming materials, and contraband into state prisons is escalating at a high rate.

“Nobody at the prisons in Washington told us this was happening,” Dillon said.

“There hasn't been a single instance I can think of where we've ever been rejected because of anything in the book, any drugs, any knives, or any tools, or anything else like that,” Chan said.

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The rule change means Washington prisoners will have to rely on prison libraries, which Books to Prisoners said are unable to keep up with demand for reading materials and are often understaffed.

Multiple calls and emails seeking comment from the Washington Department of Corrections were not returned Monday.

“If there was any indication that there had been a security risk from us or any of the other non-profit organizations that send in books, then talk to us and tell us what the security concern is and back it up with facts,” Chan said.