EL DORADO, Kan. (AP) — A man imprisoned for killing three suburban Kansas City women nearly three decades ago has lost his disciplinary appeal.

The Kansas City Star reports that Kansas Department of Corrections officials disciplined Richard Grissom Jr. for passing a sexually explicit note to a female corrections officer. Grissom is imprisoned at the El Dorado Correctional Facility for killing three young women who disappeared in June 1989.The bodies of Joan Butler, Christine Rusch and Theresa Brown have never been found.

The now 56-year-old admitted to writing the note. But he said the officer had asked him to write it — something she denied.

Grissom was sentenced to serve 30 days in segregation and fined $20. On Friday, a three-judge panel of the Kansas Court of Appeals denied Grissom’s appeal of the disciplinary action.