Right Beside You. Maggie Turner Suspense Series, #2

This dark suspense series is set in Portsmouth, Hampshire, and features British journalist Maggie Turner. They had their future all mapped out until that fateful night destroyed it. Now those responsible must pay. When Maggie receives an anonymous letter, she realises she's being stalked. The only connection is a Hampshire gang she helped put in prison thirteen years earlier. As the stalking intensifies, Maggie suspects everyone around her.
Even those she loves. But as Maggie becomes more and more paranoid, one by one the gang members suffer horrifying attacks. Someone from her past is out for revenge, and it's clear that Maggie is next .