Peter Fonda guest stars for at least two episodes of CSI: NY as Det. Mac's former partner William Hunt.
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CSI: NY Season 7 Episode 21 Quotes

Bill Hunt: Not a day went by that I didn't think of turning myself in.
Mac: But you didn't
Bill Hunt: It wouldn't have made a difference.
Mac: It would have to me.

You always walked the line, Bill, but I never thought you'd cross it.

Mac