On Borrowed Time - Rutland crime series, #2

Book two in a stunning new crime series from 2m+ international bestseller Adam Croft. Each morning, the first train of the day leaves Oakham station and thunders through a tunnel under the village of Manton. But today the driver sees something that changes his life. A dead body hangs in the tunnel's exit. DI Caroline Hills knows this isn't a suicide. It's murder. And when a second apparent suicide appears in Rutland, Caroline uncovers a shocking link: the victims knew each other. As Rutland Police fight to catch the killer, a group of friends is left with an even more shocking realisation.
One of them is the murderer. And one of them will be the next to die. 'Incredible' - BBC News'A sensation' - The Guardian