The case against Dennis Priven seemed like a slam dunk. As 23-year-old Peace Corps volunteer Deb Gardner lay bleeding to death from stab wounds, she whispered a name: “Dennis,” a fellow volunteer. Neighbors had seen Dennis fleeing Deb’s hut, where Tongan police discovered one of his flip-flops, his glasses, and his bloodstained knife. Other volunteers had spoken of his obsession with Deb. One had begged the country director to send Dennis home, saying, “He seems to be slipping off the rails.”

Employing the first insanity defense in the history of the South Pacific kingdom, Dennis eluded the gallows. And thanks to extraterritorial bullying and ugly-American trickery, he was whisked home and allowed to forgo the psychiatric hospitalization the U.S. had promised Tonga.

Author Philip Weiss spent 16 years researching this story, which he first heard while backpacking in 1978. He expertly reconstructs conversations that took place nearly 30 years ago, and shares the cherished memories of young idealists whose innocence died with Deb in October 1976. When he finally tracks down Dennis in Brooklyn, Weiss leaves us pondering a line inspired by Robert Frost: “We sit in a circle and suppose/The secret sits in the middle and knows.” Only the murderer knows for sure who killed Deb Gardner; Weiss tells us how he got away with it.