An East St. Louis man has pleaded guilty to killing a University of Missouri student after what prosecutors call a botched 2013 marijuana deal. Twenty-six-year-old Deneshion M. Swope pleaded guilty Tuesday to first-degree murder in Madison County Circuit Court in the shooting death of 21-year-old Jarrett Mosby of Collinsville. Police say Mosby and Swope got into a fight in the college student's car in the village of Madison after Swope had arranged to purchase pot from Mosby. Mosby was a senior majoring in business at the University of Missouri in Columbia. He had returned to the Illinois suburbs of St. Louis to visit his young son during the school's winter break. Prosecutors plan to seek a 40-year prison sentence. Swope remains in the county jail pending his sentencing.