LINCOLN, Neb. (AP) — A Nebraska man convicted of killing his girlfriend in 2002 is blaming an antidepressant for his actions and requesting his case be re-examined by a judge.

Randall Robbins pleaded guilty to second-degree murder in the death of 17-year-old Brittany Eurek and was sentenced to 40 to 60 years in prison.

Robbins claims the antidepressant Zoloft, which was prescribed to him in 2002, played a key role in what was supposed to be a murder-suicide.

Robbins’ attorney says DNA testing conducted this year shows genetics prevents Robbins from metabolizing Zoloft as intended by its manufacturer. His attorney says that can lead to violent outbursts and suicidal behavior, something the federal government warned of in 2007.

Briefs are expected to be submitted soon.