Craig Russell
Jan Fabel, a Scottish-German police detective (Kriminalhauptkommissar), in Hamburg, Germany:

Blood Eagle (2005)

Brother Grimm (2006)
Finalist 2007 Gold Dagger Award

Eternal (2007)

The Carnival Master (2008)

The Valkyrie Song (2009)

A Fear of Dark Water (2011)

The Ghosts of Altona (2015)

Lennox, a shady private investigator in 1950s Glasgow, Scotland:

Lennox (2009)

The Long Glasgow Kiss (2010)

The Deep Dark Sleep (2011)

Dead Men and Broken Hearts (2012)
Finalist 2013 Historical Dagger Award

Written as Christopher Galt:

Biblical (2014)