To Die In June: Alan Parks

A woman enters a Glasgow police station to report her son missing, but no record can be found of the boy. When Detective Harry McCoy, seconded from the cop shop across town, discovers the family is part of the cultish Church of Christ’s Suffering, he suspects there is more to Michael’s disappearance than meets the eye.
Meanwhile reports arrive of a string of poisonings of down-and-outs across the city. The dead are men who few barely notice, let alone care about – but, as McCoy is painfully aware, among this desperate community is his own father.
Even as McCoy searches for the missing boy, he must conceal from his colleagues the real reason for his presence – to investigate corruption in the station. Some folk pray for justice. Detective Harry McCoy hasn’t got time to wait.