Vengeance - Debt Collector 2 (A Jack Winchester Thriller);

Mobster and hitman Jack Winchester thought he had put his past behind him. When he returns to New York City and finds his friend murdered, and his sister kidnapped, Jack goes to war against the Sicilian Mafia.

Read all 9 books in the Jack Winchester series:
The Debt Collector
Debt Collector: Vengeance
Debt Collector: Reborn
Debt Collector: Hard to Kill
Debt Collector: Angel of Death
Debt Collector: Prey
Debt Collector: Narc
Debt Collector: Hard Time
Debt Collector: Her Last Breath