We Are Death — Douglas Lindsay

Morlock is coming. Death will follow.
DCI Jericho may have evaded the Hanged Man, but he knew there was something missing. He knew there was still someone out there. He knew there would be more death…
A man is murdered on the Somerset Levels, a bullet in the head from three feet. Jericho soon learns there was a connected killing the previous day in the Swiss Alps.
Death comes in the post, and quickly strands from the past become entangled: the hunted mountaineers, a long lost secret, the mystery of Jericho's wife, and the covert organisation, working in the shadows, always in control.
Joined by DI Badstuber of the Swiss police, Jericho travels across Europe to North Africa, chasing an invisible killer. But Death is always one step ahead, while his past, sinister and terrifying, is closing in.