Showing Dead of Night by Barbara Nadel

Inner-city murder crosses two continents.

Inspectors Cetin Ikmen and Mehmet Suleyman from Istanbul are sent to a policing conference in Detroit, but little can prepare them for the corruption that lies at its heart. When Ezekial Goins, an elderly man of Turkish descent, approaches them to crack the long-unsolved murder of his son, a quiet trip takes a far more sinister turn.

As they delve deeper into the case, the pair find themselves immersed in a terrifying world of intergang drug war and racial prejudice that puts them in mortal danger and forces Ikmen to confront some demons of his own....