This one has looked a bit of a mystery, with nothing at all been found to support the expectation that it hit an obstacle/crane at very low level at night.
I too saw the report on the NTSB site, and agree that wake turbulence perhaps looks the least unlikely at this point, as the investigation progresses.
Having said that, although winds were calm, 900ft below an RJ, which is not exactly huge, 1 min 45 sec after it, which I guess would approximate to say 5 miles spacing, doesn't seem too concerning I wouldn't have thought. Any other views on this?
Of course the other thing is that if that does end up being the most likely cause, the fact that it was a night EMS accident is irrelevant. Could have happened to anyone permitted on the route. More potential for statistics to mislead.