Mr Williams' uncle, Anglesey councillor William Hughes, meanwhile, said his "very talented" nephew "would never talk about his work - and the family knew not to ask, really".

BBC: Profile: MI6 spy Gareth Williams

Defense attorney William Pepper calls Rhodes-Hughes' recollections "significant verification" of new assassination evidence that the Sirhan legal team is currently presenting.

CNN: STORY HIGHLIGHTS

Before his death, Melanson published Rhodes-Hughes' statement in "Shadow Play, " a book he co-authored with William Klaber in 1997 and one of several Melanson wrote on the Robert Kennedy assassination.

CNN: STORY HIGHLIGHTS