Sipple was part of a crowd of about 3,000 people who had gathered outside San Francisco's St. Francis to see President Ford on September 22, 1975.
Ford, just emerging from the building, was vulnerable despite heavy security protection. Sipple noticed a woman next to him had pulled and leveled a .38-caliber pistol at Ford as he headed to his limousine. Reacting instinctively, Sipple lunged at the shooter, Sarah Jane Moore, just as her finger squeezed the trigger. While the gun did go off, the impact was enough to deflect her aim and cause the bullet to veer wide of its mark. The bullet hit John Ludwig, a 42-year-old taxi driver. Ludwig survived.
Sipple's mental and physical health sharply declined over the years. He drank heavily, gained weight, was fitted with a pacemaker, became paranoid and suicidal. On 2 February 1989, he was found dead in his bed, at the age of forty-seven. Earlier that day, Sipple had visited a friend and said he had been turned away by the Veterans' Administration hospital where he went concerning his difficulty in breathing.
Sources: wikipedia.org, gayfortoday.blogspot.com