Stalking Horse — Collin Wilcox

A senator's life is in danger -- and anyone in San Francisco could be a killer
Senate majority leader Donald Ryan is a kingmaker, with the power to make or break presidencies, and the ability to reshape the country with a flick of his pen. He is also a very sick man, recovering from a heart attack that must be kept secret at all costs. But when a series of death threats jeopardizes his planned return to public life, the FBI calls in San Francisco police lieutenant Frank Hastings to find the would-be assassin. He has one week until the senator's next public appearance -- and hundreds of thousands of possible suspects.
Because Ryan's recent heart attack is considered a state secret, Hastings is forced to withhold crucial details from his fellow detectives. Any degree of stress could stop the senator's fragile heart, which means that even if a bullet misses, the sound of the  gunshot might be enough to kill him. To save the lawmaker, Hastings may have to put himself in the line of fire.