Intermediate Documentary Filmmaking - S2-E16
Deliberate mistake: This episode is meant to be entirely a documentary made by Abed. At the end of the episode, there's a shot where the gang is looking into Pierce's window, except the camera is right in front of the window they're looking through. If Abed was filming this he would literally be right in front of the gang, completely obscuring their view through it.
Answer: His attempt to "kill" Jeff was to roll at him as an iPad on a stick. He knew it wouldn't work, but it played to the story that he was a killer as he knew Jeff would tell people about it, or attempt to retaliate for it.