Talk at Newsarama has some strong theories in support of Jean as the killer. She has motivation (wanting super-heroes to do things differently concerning loved ones), she has the 'tool' (Ray's belt), and the time frame fits (she probably did it while 'waiting' for Ray to show up). Interesting shtuff. Though she'd have to have figured out how to start a fire on a sub-atomic level for Sue to be torched. Course that may not be the case.
I wonder if there's more to Batman not wanting J'onn in his head.
