Escape Clause by John Sandford

When two rare Amur tigers are stolen from the Minnesota Zoo, Virgil Flowers is called in to find them before they vanish into the black market. The crime seems straightforward — until one of the thieves turns up dead and the other disappears.

As Virgil digs deeper, he uncovers a network of smugglers, animal traffickers, and ruthless buyers willing to kill for profit. Meanwhile, his girlfriend Frankie is fighting a battle of her own when her sister arrives in town — and brings chaos with her.

The hunt for the tigers becomes a race against time, forcing Virgil to confront predators of a different kind — the human ones.