The Man Who Knew

This is a mystery novel that tells the story of Philip Lashbrook, a diligent and observant sergeant who is the best in his field. Having completed the mission assigned to him by his superior officer and thus being more or less off duty, he is summoned by a stranger who discovers the body of a man. Lashbrook's suspicions are immediately directed at the stranger, who immediately denies being the murderer. Will Lashbrook follow his instinct and arrest the stranger?