City of Destiny — Brian O'Neill

Fast friends since childhood, police sergeant Michael Cassidy and Lieutenant Nate Orlando have served side by side for years. But everything changes when a woman comes between them and the bloodiest gang war Tacoma, the City of Destiny, has seen in decades erupts on their watch. Cassidy alone believes the Mexican Mafia is responsible, but no one is likely to believe a demoted alcoholic cop, especially when his best friend turns his back on him.
In a whirlwind of shootings, drug deals, and deception, Cassidy and Francine “Echie” Echevaria, a sultry gang cop he's fallen for, must act quickly -- or become the next victims. City of Destiny grabs the reader from the start and never lets go as it follows the violent twists and turns of a cop trying to keep his life on track and doing his best to keep the drug lords from killing everyone in their path.