FRANKFORT, Ky. — A human rights group says the Kentucky Department of Corrections is illegally censoring books the group has sent to prisoners.

The nonprofit Human Rights Defense Center said it filed a lawsuit against the department this week in federal court in Frankfort.

The Defense Center says it sent 158 books to Kentucky prisoners in the past year and dozens were rejected for a variety of reasons. Among them the Merriam-Webster Dictionary of Law, the Prisoner Diabetes Handbook and the Prisoners’ Self-Help Litigation Manual.

According to the Defense Center, the department’s policies of banning books not directly purchased by prisoners and those not included on a pre-approved vendor list violates the First Amendment right to free speech and 14th Amendment rights to equal protection and due process.

A department spokesman didn’t immediately respond to a request for comment Thursday.