A and E did a pretty decent treatment of Chappaquidick a few years ago. They probably replay it sometimes, though I haven't noticed it lately. I seem to recall it was pretty critical of TK, but maybe someone else remembers it better.
Did the (25th?) anniversary of Chap coincide with the death of JFK jr? I seem to recall that the A&E show was on a few days before the plane went down. After that happened, no othe network would put on a show they may have had ready.