I agree...the parking lot scenario and firing from a vehicle has some merit would explain NO casings for example...I played some what ifs and could have added one shooting south on Conneticut but figure we could see the really obvious...and looked at what paths were basically unobstructed that provided natural cover...and saw that the area in the pink would be a great place to "sneak" around...get comfortable...hide a vehicle...get off a shot be hidden from view...and have vehicle hidden too for a casual drive away...and drive OFF in another direction away from the chaos...what do you think? Could even be in the parking lot across the street from the pink area...and fire off a shot...I think the large building between the gas station and the pink area...is great cover to allow a sniper to walk off...and get in a car and drive away...
