WICHITA, Kan. (AP) — Two civil rights groups are suing the Wilson County sheriff over his jail’s policy of allowing inmates to receive and send only postcards in the mail.

The American Civil Liberties Union and the Social Justice Law Collective contend the policy violates the free speech and due process rights of prisoners and the people who write to them.

Their class-action lawsuit, filed Thursday in U.S. District Court of Kansas, seeks a court order that puts an end to the practice.

Wilson County Sheriff Pete Figgins did not immediately return a phone message seeking comment.

SJLC attorney Joshua Glickman says post-card only mail policies have appeared across the country in the past six or seven years as a cost-cutting measure. He says they have been overturned or rescinded when challenged.