The body of a Mount Vernon man who has been missing since Sunday evening was found yesterday.  According to the Jefferson County Coroner Eddie Joe Marks, 43-year old Jason Johnson was found in the northeastern part of Jefferson County, not far from his automobile, by a Jefferson County Sheriff’s deputy who was assisting the Illinois State Police.  The ISP had found an abandoned vehicle that had registered to Johnson and he was found within a quarter mile from that vehicle.  It was determined that he died due to a self-inflicted gunshot wound.   Johnson was pronounced dead by Marks at 5:18 PM.   Johnson was taken to the Brayfield- Gilbert Funeral Home in Sesser.