In seeking a new murder trial, Kennedy cousin Michael Skakel is counting on the credibility of a former tobacco executive who once posed as an attorney and later lied about being kidnapped, colleagues and authorities say.

Skakel, a nephew of Ethel Kennedy, is serving 20 years to life for beating a Greenwich neighbor to death with a golf club in 1975. But after Skakel’s conviction in 2002, Gitano “Tony” Bryant told Skakel’s attorneys that his two friends may have killed 15-year-old Martha Moxley. Based on that claim, Skakel’s attorneys want a new trial. But to get there, Bryant’s believability will be put to the test.