Former AP Mexico bureau chief Katherine Corcoran’s pulsating investigation into the murder of a legendary woman journalist on the verge of exposing government corruption in Mexico.

Regina Martínez was no stranger to retaliation. A journalist out of Mexico’s Gulf Coast state of Veracruz, Regina's stories for the magazine Proceso laid out the corruption and abuse underlying Mexican politics. She was barred from press conferences, and copies of Proceso often disappeared before they made the newsstands. In 2012, shortly after Proceso published an article on corruption and two Veracruz politicians, and the magazine went missing once again, she was bludgeoned to death in her bathroom. The message was clear: No journalist in Mexico was safe.

Katherine Corcoran, then leading the Associated Press coverage of Mexico, admired Regina Martínez’s work. Troubled by the news of her death, Corcoran journeyed to Veracruz to find out what had happened. Regina hadn’t even written the controversial article. But did she have something else that someone didn’t want published? Once there, Katherine bonded with four of Regina’s grief-stricken mentees, each desperate to prove who was to blame for the death of their friend. Together they battled cover-ups, narco-officials, red tape, and threats to sift through the mess of lies—and discover what got Regina killed.

A gripping look at reporters who dare to step on the deadly “third rail,” where the state and organized crime have become indistinguishable, In the Mouth of the Wolf confronts how silencing the free press threatens basic protections and rule of law across the globe.