Books like Chaos in Death by Nora Roberts

“This is a random universe,” Reacher says. “Once in a blue moon things turn out just right.” This isn’t one of those times. Reacher is on a Greyhound bus, minding his own business, with no particular place to go, and all the time in the world to get there. Then he steps off the bus to help an old man who is obviously just a victim waiting to happen. But you know what they say about good deeds. Now Reacher wants to make it right. An elderly couple have made a few well-meaning mistakes, and now they owe big money to some very bad people. One brazen move leads to another, and suddenly Reacher finds himself a wanted man in the middle of a brutal turf war between rival Ukrainian and Albanian gangs. Reacher has to stay one step ahead of the loan sharks, the thugs, and the assassins. He teams up with a fed-up waitress who knows a little more than she’s letting on, and sets out to take down the powerful and make the greedy pay. It’s a long shot. The odds are against him. But Reacher believes in a certain kind of justice . . . the kind that comes along once in a blue moon.

"Lucas Davenport confronts an old nemesis, now a powerful U.S. senator, in the thrilling new novel in the #1 New York Times-bestselling Prey series. Lucas Davenport had crossed paths with her before. A rich psychopath, Taryn Grant had run successfully for the U.S. Senate, where Lucas had predicted she'd fit right in. He was also convinced that she'd been responsible for three murders, though he'd never been able to prove it. Once a psychopath had gotten that kind of rush, though, he or she often needed another fix, so he figured he might be seeing her again. He was right. A federal marshal now, with a very wide scope of investigation, he's heard rumors that Grant has found her seat on the Senate intelligence committee, and the contacts she's made from it, to be very ... useful. Pinning those rumors down was likely to be just as difficult as before, and considerably more dangerous. But they had unfinished business, he and Grant. One way or the other, he was going to see it through to the end"--

"I very much need to be dead." These are the chilling last words left by a man who had everything to live for but took his own life. In the void that remains stands his widow, FBI agent Jane Hawk, surrounded by questions destined to go unanswered unless she does what all the grief and fury inside her demand: Find the truth, no matter what. People of talent and accomplishment, people seemingly happy and sound of mind, have recently been committing suicide in surprising numbers. A disturbing pattern is beginning to emerge. Jane is determined to give up everything to find out why. And if that means going rogue and becoming America's Most Wanted, then so be it. Those arrayed against her are legion, and devoted to protecting something profoundly important-or terrifying-enough to exterminate any and all in their way. But Jane is as clever as these enemies are cold-blooded, as relentless as they are ruthless. And she is driven by a righteous rage they can never comprehend. Because it is born of love.