DES MOINES, Iowa (KCCI-TV) — A western Iowa man recently accused of murder in a 1989 cold case is pleading not guilty. 61-year-old Robert Allen Davis was arrested in March and charged with first-degree murder, 36 years after the disappearance of Barbara Lenz, his then-girlfriend. Davis, then 25, is believed to be the last person to see Lenz, 31, before her disappearance. Lenz, who lived in Woodbine, has not been seen since. Her body has not been found.

Davis filed a written plea of not guilty in court documents filed Monday morning in Harrison County. Court records say Lenz told others she was scared of Davis just days before her disappearance, and feared he would “kill her if she ever left.” A criminal complaint alleges Davis had assaulted Lenz several times during their two-year relationship, including multiple incidents where he strangled her.

The documents show Davis admitted in 1989 to assaulting Lenz and having a violent temper.