A Riley County man convicted of reckless second-degree murder for killing an insect exterminator in 2008 is heading back to trial.

The Kansas Supreme Court on Friday reversed the conviction of Howard Barrett, 61, saying the decision to not instruct the jury of imperfect self-defense voluntary manslaughter may have affected the trial’s outcome. This form of manslaughter is defined as “an intentional killing done with unreasonable but honest belief that circumstances existed justifying deadly force.”

In 2008, Barrett, 61, attacked and fatally stabbed Thomas James, 48, when James entered his Leonardville apartment to spray for bugs. Evaluations determined Barrett was not competent to stand trial until 2014, and evidence showed Barrett suffered from schizophrenia and felt threatened by James.

During the trial, the Riley County District Court instructed the jury on the mental disease but denied Barrett’s request for an instruction on imperfect self-defense voluntary manslaughter. Barrett was found guilty and sentenced to more than 10 years in prison.

Barrett appealed and argued the court erred in not instructing the jury per his request, but the Court of Appeals held the the error was harmless.

The Supreme Court disagreed, remanding the case for a new trial.