Saw on the news a witness saw an engine on fire before it went down. Not sure how credible.
On another note, my boss gave me a letter from Cessna three days ago stating their concern that owners and operators have not been complying with the exhaust AD that plagues the twin Cessnas. We have been compliant, but the memo basically said that some reports from overhaul shops had seen significant increase in aircraft with damaged exhaust. Those aircraft were not keeping up with the 50 hr inspections or the other inspections involved.
This is no speculation on the cause of the crash, just a reminder to be good with MX. AD's are out for a reason.