The Last Policeman by Ben Winters is a police procedural / mystery that manages to be very
interesting & massively depressing.
The depressing part is produced courtesy of the book’s setting --- it is
set in a near future Earth that is 6 months away from being struck by an
asteroid. This asteroid is big enough
that it will wipe out half the population on impact and leave the survivors
with near intractable environmental change, or a slower death. In this world we have one policeman, Hank
Palace, who begins investigating a suicide that he believes is murder. The investigation takes him far and wide
& he does eventually solve the crime.
The reader is left to wonder about what you would do in a similar
situation.