Homicide

Oklahoma judge to decide competency of man in father's death

  • Christian Costello, accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015, waits for a competency hearing in an Oklahoma County courtroom in Oklahoma City, Wednesday, Aug. 10, 2016. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)

    Christian Costello, accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015, waits for a competency hearing in an Oklahoma County courtroom in Oklahoma City, Wednesday, Aug. 10, 2016. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)  (The Associated Press)

  • David Prater, Oklahoma County District Attorney, talks to the media following a a competency hearing for Christian Costello in Oklahoma City, Wednesday, Aug. 10, 2016. Christian Costello is accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)

    David Prater, Oklahoma County District Attorney, talks to the media following a a competency hearing for Christian Costello in Oklahoma City, Wednesday, Aug. 10, 2016. Christian Costello is accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)  (The Associated Press)

  • Christian Costello, left, accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015, is led from a competency hearing in an Oklahoma County courtroom in Oklahoma City, Wednesday, Aug. 10, 2016. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)

    Christian Costello, left, accused of fatally stabbing his father, former Oklahoma Labor Commissioner Mark Costello, in August of 2015, is led from a competency hearing in an Oklahoma County courtroom in Oklahoma City, Wednesday, Aug. 10, 2016. Costello was ordered to be returned to a state mental hospital to be examined by a psychiatrist hired by prosecutors. (AP Photo/Sue Ogrocki)  (The Associated Press)

An Oklahoma judge is scheduled to decide whether a man accused of fatally stabbing his father, the state's former labor commissioner, is mentally competent to plead guilty to a first-degree murder charge.

Prosecutors say Christian Costello repeatedly stabbed his father, Mark Costello, at an Oklahoma City restaurant on Aug. 23, 2015. Christian Costello has pleaded not guilty.

District Judge Ray Elliott ordered a competency evaluation in May after Christian Costello said he wanted to change his plea. Costello's attorney, Bob Ravitz, has said he has a history of mental illness and that he believes Costello was legally insane and did not know right from wrong when he attacked his father.

The competency hearing is scheduled for Wednesday in Oklahoma County.