Mr. Mercedes (Bill Hodges Trilogy, #1)

"In the frigid pre-dawn hours, in a distressed Midwestern city, hundreds of desperate unemployed folks are lined up for a spot at a job fair. Without warning, a lone driver plows through the crowd in a stolen Mercedes, running over the innocent, backing up, and charging again. Eight people are killed; fifteen are wounded ... In another part of town, months later, a retired cop named Bill Hodges is still haunted by the unsolved crime. When he gets a crazed letter from someone who self-identifies as the 'perk' and threatens an even more diabolical attack, Hodges wakes up from his depressed and vacant retirement, hell-bent on preventing another tragedy"--