McGurley was a hard-nosed, hard drinking detective for twenty years. He played by his own rules, and always got the job done. Anyone who knows him knows you just don't fuck with McGurley: with a name like that, you learn to stand up for yourself pretty damned early if you want to survive in the school yard. In 2009, McGurley found out his Lieutenant was on the take from the Russian mob. His Lt. threatened him, so McGurley killed him. In prison, the Russkies sent some guys to shiv him. So he killed 'em too. You just don't fuck with McGurley.