For three decades after the Second World War, the 'Butcher of the Balkans' lived an idyllic life with his family in a Los Angeles suburb. Andrija Artuković was a senior member of the Ustasha, a Croatian fascist and nationalist movement, and was responsible for the wartime murders of hundreds of thousands of men, women and children. Wanted in Yugoslavia to stand trial for war crimes, he had illegally entered and claimed political asylum in the United States – and his powerful supporters sought to keep him there.

Meanwhile, just 10 miles away, David Whitelaw lived with his mother, Judith, who fled Germany in 1938. Seventy-six of her relatives were killed in the Holocaust. When David learned Artuković was living comfortably nearby, he vowed to ensure his deportation to stand trial as a war criminal. But when a firebomb, thrown with the sole intention of causing fear, saw the young man sent to jail, a battle began for his own freedom, while the war criminal remained at large.

A true David-versus-Goliath battle, The Fierce is the story of the teenager who helped take down the worst mass murderer and war criminal in America.