The ridge high above Los Angeles is filled with clues. There are shattered pieces of electrical equipment, and a grove of madrone blackened by fire. Police tape is strung around one section of the sandy soil, now mixed with ash. Investigators have zeroed in on these rocky bluffs with sweeping views of the Pacific Ocean as the ignition point of the Palisades fire, the inferno that has destroyed at least 5,000 homes and businesses and killed at least eight people. A recent visit by New York Times reporters to the site — near the “crime scene,” as officers for the...