Dorthy Moxley, the mother of Martha Moxley, died at 92 in New Jersey Tuesday, according to her son, John.
Her daughter was beaten to death with a golf club in 1975 in Greenwich's Belle Haven neighborhood.
In 2002, Kennedy cousin Michael Skakel was convicted of killing Moxley. He was released on bond in 2013 after an appeals court overturned the verdict.
Moxley is survived by two grandchildren in addition to her son.