It's Best to Shoot in the Head - a thriller by Shayne Youngblood

"If you hide in hell, nobody'll come calling."
Those are words to live by for Youngblood, an American who escapes fraud charges in Las Vegas by hiding in a war-torn Balkan town in 1996. The city he's chosen for his shelter, Belgrade, Serbia, is hell—or paradise. Depends who you ask. Crime-ridden, ruled by decaying dictatorship and corruption, the city is perdition for everyone but Roko, a crime kingpin at his prime.
Irony has it that the worst place on Earth has the world’s most beautiful women, and Youngblood marries the most seductive of the fallen angels—Roko’s sister.
His dreams of a safe haven under the protection of his mob boss brother-in-law evaporate after a night of weakness, and Youngblood is soon in over his head. Drawn into a gang war, he ends up shooting the younger brother of a notorious Department of State Security enforcer, the Beast.
Roko fears no man. But Beast is no ordinary man. He's a top assassin whose legendary career ended because his ways were too horrendous even for the hardened State Security brass.
Youngblood's world spirals out of control when Beast threatens to avenge his kid brother by killing Roko's sister, Youngblood's wife—unless they turn over his brother’s shooter. Without Roko's protection, Youngblood is between a rock and a hard place: he must trade his own life to save his loving wife.