Safe house - Andrew H Vachss

Burke - hard-core criminal and man-for-hire - is up against a new breed of predator: stalkers. Some obsessed, some deranged, all dangerous. A beautiful outlaw hires Burke to shield one of her charges from a vengeful ex with a fetish for Nazism. But the stalker has a protector who can shut down her operation for good.
When Burke learns that the extortionist might be government-issue, and that the stalker is a member of a neo-Nazi cell with plans to make Oklahoma City look like a pipe-bomb, his survivalist instincts go on full alert. And when it comes down to making his own house and his family-of-choice safe, Burke turns lethal.