MONTEZUMA, Iowa (AP) — A hearing to determine whether key evidence can be used against a man charged in the killing of University of Iowa student Mollie Tibbetts has been delayed.

Cristhian Bahena Rivera is charged with murder in the July 2018 killing.

Prosecutors acknowledged last week that officers didn’t read Rivera his rights during an interrogation before Tibbetts’ body was recovered.

A court official says a hearing scheduled for Tuesday to decide if the information from that interrogation could be used to rebut testimony has been postponed because a defense lawyer’s parent has died. It will be rescheduled.

The 25-year-old man is scheduled for trial in February.

Prosecutors allege Rivera stalked Tibbetts while she was running near her hometown of Brooklyn, stabbed her to death and dumped her body in a cornfield.