From the TSO Facebook page:
The entire Trans-Siberian Orchestra family, past and present, is heartbroken to share the devastating news that Paul O’Neill has passed away from chronic illness.
He was our friend and our leader -- a truly creative spirit and an altruistic soul. This is a profound and indescribable loss for us all.
We ask that you respect Paul’s family’s privacy now.
We will make additional announcements shortly.
Trans-Siberian Orchestra formed in 1996. In 2009, Billboard magazine ranked TSO at #25 on its "Top Touring Artists Of The Decade with tour grosses of over $625 million, and 12+ million albums and DVDs sold over the past 20 years.