Stephen Gallagher 
Red, Red Robin [EPUB ebook] 

When Ruth Lasseter hires an escort to cover for a workplace affair, she lets a deeply disturbed young man into her life. Though she survives the consequence, she’s left with the lingering suspicion that he hasn’t simply disappeared. He’s still out there, taking out his problems on other woman just like her.There was a moment when Ruth had her chance to stop him for good. But she didn’t take it.Now she sees that closure-for both of them-lies on the other side of that line.