One of two men accused in the death of a Hannibal convenience store clerk last fall enters a guilty plea. Michael Studer has entered a guilty plea in Boone County to second degree murder charges. He is sentenced to 25 years in prison.  Gary Wiltermood also faces second degree murder charges in connection with the October 8th shooting death of Adrienne Arnett at the Abel’s Quik Shop on Shinn Lane west of Hannibal. Both cases were moved from Marion County on a change of venue.