MSU alumnus Tyler Aho, left, demonstrates the grappling and actions of defendant Connor McCowan with detective in charge of the investigation, Meridian Township police Sgt. Andrew McCready during the preliminary exam for the teen accused of stabbing MSU student Andrew Singler to death, April 18, 2013, at Ingham County District Judge Donald Allen’s courtroom in Mason, Mich. Aho was Singler’s roommate and witnessed the altercation. Natalie Kolb/The State News