Dekker 2 in 1 (Obsessed & Three) by Ted Dekker

Three: Enter a world where nothing is what it seems. Where your closest friend could be your greatest enemy. Kevin Parson is driving his car late one summer day when, suddenly, his cell phone rings. A man who identifies himself as Slater speaks in a breathy voice: You have exactly three minutes to confess your sin to the world. Refuse, and the car you're driving will blow sky high. Kevin panics. Who would make such a call? What sin? Kevin ditches the car. Precisely three minutes later, a massive explosion sets his world on a collision course with madness. From the #1 best-selling fiction author comes a powerful story of good, evil, and all that lies between.

Obsessed: A deadly tale of ultimate obsession. Stephen Friedman is making a good living in good times. He's just an ordinary guy. Or so he thinks. But one day an extraordinary piece of information tells him differently. It's a clue from the grave of a Holocaust survivor. A clue that makes him heir to an incredible fortune...a clue that only he and one other man can possibly understand. That man is Roth Braun, a serial killer who has been waiting for Stephen for thirty years. Roth was stopped once before. This time nothing will get in his way. Known worldwide for page-turning, adrenaline-laced thrillers, Dekker raises the stakes in this story of passion, revenge, and an all-consuming obsession for the ultimate treasure.