The sentry - Robert Crais

Dru Rayne and her uncle are Louisiana refugees who relocated to Los Angeles after Hurricane Katrina. Now, five years after the storm, their struggling restaurant faces a different danger. When Joe Pike witnesses Dru's uncle beaten by a neighborhood gang intent on extorting protection money, he offers his own brand of protection. But neither Dru nor her uncle want his help - and neither do the federal agents mysteriously watching their store -- agents who seem more than willing to let the gang have their way.
But Pike is falling for Dru, and won't back away whether she wants his help or not. As the violence escalates, the gang targets Pike, who, with Elvis Cole's help, learns that Dru and her uncle are not who they seem. It soon emerges that everything Pike thought he knew about them, their relationship to the gang, and the reasons they fled New Orleans have been lies. Now, a vengeful and murderous force from their past is catching up with them, pitting Pike and Cole against the combined forces of South American crime lords, rogue federal agents, and contract assassins on the bloody hunt for twelve million dollars in missing stolen cash.