On whether or not he's a "Collector"... It's looking like, at the very least, he's accumulating crimes/memories... A while back it was being discussed how a lot of the disappearances in VA were in the Fall, around the time school would start. I also believe (not sure) that JM's alleged rapes were often around that time of year. If - and we're being hypothetical here - JM were responsible for a good chunk of those disappearances, each in Fall, each a young, intoxicated, woman... It sounds (just sounds) like Hannah's shirt was not found with the body, but her pants were. Morgan's shirt was not with the body.
It sounds very habitual, very ritualistic. He sounds like he treats these crimes as an event that he anticipates, gets excited for... It's something he cares about. He may very well keep many, many, many trophies, not just the one or two generally kept by those types of serial killers. He could have Hannah's shirt on display somewhere and her watch/bracelet, undergarments, cell phone... Somewhere on or near his property.
Don't want to keep bringing up Mickey over and over and over, but early on, LE found her ID and Lisa Pate's ID in his apartment. They kept it quiet for months, but that was why they knew it was him. LE didn't behave as though they found very much in JM's apartment... But they certainly seemed to think, if quietly, that he was their guy.
I'll be very interested to see what information comes out in the coming months. Everyone, including me, thinks that the Cville PD was shockingly forthcoming with information. There may have been so much information that there's still plenty to come. Maybe they already knew of the link with Morgan and were pushing JM to his limits with the Hannah investigation.
Sorry for the long post! Anyway, this should be interesting.