23 September 2010,
Matt from Fancast answered a question on whether James Marsters would return to Hawaii Five-0:

Q: I caught a sneak peek of CBS’ ‘Hawaii Five-O‘ and loved it! Will James Marsters be back? He’s such a good bad guy. – Melissa

A: When I asked ‘H50′ exec producer Alex Kurtzman that question at TCA, he said that McGarrett & Co. will contend with “several recurring bad guys,” Marsters’ Victor Hesse perhaps included. But with James currently busy filming the Syfy pilot ‘Three Inches,’ “Nothing is confirmed as of yet,” a CBS rep informs me.

Labels: CBS, Hawaii Five-O, James Marsters, Season 1, Spoiler