State Police have identified the second person who was killed in a bizarre car crash Tuesday on the Martha’s Vineyard estate owned by Caroline Kennedy. Susan Lombard of Lyman, N.H., was the front seat passenger in the car. State Police had previously said that Judith Morse, 70, of West Tisbury died in the crash. The rear seat passenger, Susan Papanicolaou, 68, of Minneapolis, suffered minor injuries. State Police said today they continued to investigate the crash on the Aquinnah estate, which was reported at 12:10 p.m. Tuesday. They said they were probing several possible factors, including driver error, a medical incident, or mechanical failure.