Speculation is all we have for now, but from the NTSB stub it looks like icing is not likely under visual meteorological conditions during the event. Otherwise, that would be my first guess. My next guess is engine or systems failure, followed by pilot error. The latter is the cause of most aircraft accidents unfortunately, and if the pilot was distracted on takeoff by something and lost both instrument and visual reference even momentarily at such low altitude, a CFIT (controlled flight into terrain/obstacles) accident may have been the result. We will not know until the NTSB investigation come back with what they find, engine and systems checks can take a while if metallurgy and other specialties are required. Airplanes being such complex machines, it can take a while to analyze everything.
We feel for your loss.