WICHITA, Kan. (AP) — A federal judge has granted class action status to a lawsuit filed against the Wilson County sheriff over his jail’s policy of allowing inmates to receive and send only postcards in the mail.

U.S. District Judge Julie Robinson on Thursday granted the request for class certification. The class would cover at least 40 people, the average daily inmate population at the jail.

The American Civil Liberties Union of Kansas and the Social Justice Law Collective sued Figgins in April alleging the policy violates the free speech and due process rights of prisoners and the people who write to them.

Sheriff Pete Figgins has defended the policy saying some people use coded language or plant a letter in sealed envelopes meant for someone whom they’re not supposed to contact.