WASHINGTON (AP) — There must be an answer.

Whatever is harming U.S. diplomats in Havana, it's eluded the doctors, scientists and intelligence analysts scouring for answers. Investigators have chased many theories, including a sonic attack, electromagnetic weapon or flawed spying device.

Each explanation seems to fit parts of what's happened, conflicting with others.

The United States doesn't even know what to call it. Secretary of State Rex Tillerson used the phrase "health attacks." The State Department prefers "incidents."

Either way, suspicion has fallen on Cuba. But investigators also are...