Alastair Thorne
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Thorne was a lieutenant onboard the battlestar Pegasus. He survived the attack and a subsequent boarding attempt by Cylon forces, only to be mysteriously killed sometime after Cain's discovery of the Galactica and her fleet.
His death was the impetus for Cain to arrest Karl C. Agathon (Helo) and Galen Tyrol, summarily court martialing them. (Pegasus)