The last assassin - Barry Eisler

When John Rain learns that his former lover, Midori, has been raising their child in New York, he senses a chance for reconciliation, perhaps even redemption.
But Midori is being watched by Rain's enemies, and his sudden appearance put mother and child in terrible danger.

To save them, Rain is forced to use the same deadly talents he had been hoping to leave behind.
With the help of Tatsu, his friendly nemesis in the Japanese FBI, and Dox, the ex-marine sniper whose laid-back style masks a killer as deadly as Rain himself, Rain races against time to bring his enemies into the open and eliminate them forever.
But to finish the job, he'll need one more ally: Israeli intelligence agent Delilah, a woman who represents an altogether different kind of threat ...