Tripathi resembles #2, but Tripathi is described as 6’2, and #2 looks shorter than that. UNLESS #1 is 6’5 or more. I think the man who killed the MIT cop was described as very tall.
There is a picture of him out there standing behind the spectators where he (white hat) dropped the second bomb. He stands a good 4-6 inches above most everyone else in the picture. White hat could easily be 6’1 or 6’2.