I still find it weird how one person can pull off fleeing the scene but not to get rid of their backpack and just go home and resume their routine.
What makes it even less believable for me is that it was a ghost gun. As long as he cleaned his finger prints off, it would have basically removed the most important piece of evidence.
The only reason I can think of is that he wanted to be caught (maybe to become a martyr) or the more likely solution that it wasn’t him but he is gonna get the book thrown at him regardless (hence maybe why he is taking the plea deal, given his celebrity status he could be set for life if he gets out soon enough).