This is all rumor, and probobly will not be confirmed until at least the initial accident report comes out, but he may have been found with the POH in his lap and one of the engines feathered. Neither one neccessarily means anything at this point, but there is a question on whether he was attempting a single engine takeoff.
Also, apparently he made a large number of runs down the runway.
It is a short runway at only 1100 ft, but to be doing a 30 minute runup and making multiple high speed runs or aborted takeoffs down the runway doesn't seem to bode well for whatever was going on.