Doppelganger's Curse by Milo James Fowler
A woman stalked by her double. A detective in over his head. In a city where the cops are on a mobster's payroll, private investigator Charlie Madison stands in the gap. When a wealthy young socialite asks him to help her catch a threatening stalker, he takes the case. But things aren't what they seem, and Madison has to act fast before he's framed for murder.
The Wrong Tom Jacks by Simon Kewin
Simms is employed to locate the genetic code of Tom Jacks. But not the rock star Tom Jacks, just an unknown namesake. The job bugs Simms; something about it is wrong. Someone's playing him. Problem is, he doesn't know who or why. None of the illegal tech filling his brain is much use. And the one person who can help him is also the one person on the planet who never wants to speak to him again.
Tripler: The Beginning by Neil Vogler
An impossible virus is giving people the ability to summon two identical versions of themselves into existence at any time – sending them violently insane as a side-effect. They call the infected Triplers. Harry Allwear is an operative working for an organization dedicated to wiping out the Tripler menace. But after a mission goes wrong and a dangerous target gets the better of him, Harry regains consciousness to find his worst fear realized: he's been deliberately infected.