MOSCOW, Idaho - A Moscow man sentenced to life in prison for the 2015 shooting deaths of three people and the wounding of a four others is trying to withdraw his guilty plea.

John Lee in 2016 entered an Alford plea, which means he admitted he engaged in conduct that led to the deaths of three people and admits there is evidence to convict him beyond a reasonable doubt. Lee filed a motion on Wednesday to withdraw that plea.

He has been appealing his plea for more than a year, arguing his untreated mental health conditions clouded his judgment.

Lee previously was sentenced to life for first-degree murder in connection with the deaths of his adoptive mother, 61-year-old Terri L. Grzebielski; his landlord, 76-year-old David M. Trail; and restaurant manager Belinda G. Niebuhr, 47. Lee also received a sentence of 15 years for aggravated assault in the wounding of Michael M.M. Chin, 40, of Seattle.

In March, Lee told the court he was experiencing "paranoid thoughts" and "voices" at the time of the shootings.

The judge is taking the latest motion under advisement.

KLEW and the Associated Press contributed to this report.