(AP) — An Omaha man who says he was under the influence of drugs when he fatally stabbed his roommate will serve at least 15 years in prison.

According to court records, Gregory Dodds was recently sentenced to 30 to 45 years in prison. He will serve at least 15 years under state sentencing guidelines.

Dodds pleaded no contest to second-degree murder in September in the March 2012 death of 22-year-old Verdant Patel, an engineering student at the University of Nebraska Omaha.

Two doctors say Dodds was insane at the time of the stabbing because of his extensive use of K2, a synthetic substance designed to mirror marijuana. State law says use of drugs is not a defense for insanity.