Caution wake turbulence departing DH8 (?)

http://aviation-safety.net/news/newsitem.php?id=1922

Quote:

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18 OCT 2007 Excel-Jet sues FAA over Sport-Jet VLJ crash
Excel-Jet filed a suit against the FAA in an effort to prove that its very light jet airplane and pilot were not at fault in an accident in 2006. On June 22, 2006, the Sport-Jet rolled aggressively to the left immediately after liftoff and crashed.
The company has long contended that wake turbulence was the cause, but the NTSB report, completed in April, found `it is most likely that the wake vortices were neither strong enough nor close enough to the Sport-Jet to cause the violent roll to the left.` The NTSB cited `a loss of control for an undetermined reason` as the probable cause of the accident.
Excel-Jet claims the crash happened because air traffic controllers cleared the jet to take off behind a de Havilland DHC-8 in violation of mandatory separation requirements. (AVweb)

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Excel-Jet MTOW: 4,900 lbs
Dash-8 MTOW: 64,500 lbs

Excel-Jet Engine: Single 1500lb thrust turbofan (I can't do the math right now, but that converts to under 2,000hp)
Dash-8 Engine: 2× Pratt & Whitney Canada PW150A turboprops, 5,071 hp (3,781 kW) each

So yes, given the size differences, I think it could have been a problem.

as long as first airplane departing is larger and heavier than the second airplane departing a wake turbulence caution should be issued.

From what I have been reading in different publications, NTSB has cited a good number of reasons why wake turbulence could not have been a factor in the crash.
On the other hand, they did not find any problems with the airplane either...