THE authorities investigating the death of Mary Jo Kopechne have caused nearly as much uncertainty as Edward Kennedy's own partial explanations of the accident that killed her. At first, there was almost total reluctance in Martha's Vineyard, Mass., to press the inquiry. Kennedy's plea of guilty to a charge of leaving the scene of an accident seemed to end the legalities. Now, at least one more chapter in the tortured proceeding is assured.
Exactly 21 days after Kennedy's Car plunged off the narrow Dike Bridge on Chappaquiddick Island, District Attorney Edmund Dinis and District...