By Kyle Schwab Staff Writer kschwab@oklahoman.comAn Oklahoma County judge Wednesday ordered a mental competency exam for Christian Erin Costello after the murder defendant attempted to plead guilty to fatally stabbing his father, Labor Commissioner Mark Costello. Christian Costello, who has been treated in the past for mental illness, told District Judge Ray Elliott he wanted to go to prison in Minnesota to be near a doctor who made him a Freemason about a decade ago.