The sentinel / Lee Child and Andrew Child.

"Andrew Child is the author of nine thrillers written under the name Andrew Grant."

When Reacher ends up in a town near Pleasantville, Tennessee, there's nothing pleasant about the place. When he spots someone walking into an ambush, the odds are four against one-- until Reacher intervenes, with his own trademark brand of conflict resolution. The man he saves is Rusty Rutherford, an unassuming IT manager, recently fired after a cyberattack locked up the town's data, records, information... and secrets. Rutherford wants to stay put, look innocent, and clear his name. But the guys who jumped Rutherford are part of something deadly. Now Reacher is involved in conspiracy, a cover-up, and murder-- all centered on a mousy little guy in a coffee-stained shirt who has no idea what he's up against.