Pure Killers by Eva Heart

Eleanor once dreamed of a perfect life: a family, a home, a future.
But that dream shattered the night her husband was savagely murdered.

Two years later, Eleanor has rebuilt herself, trading her grief for purpose. And she knows exactly who is to blame for destroying her life, because he’s active again, and she’s the detective on his case
Needler needs to pay for his crimes against the city, and against her.
But the city doesn’t want Needler stopped. They call him a vigilante, targeting only the corrupt and wicked. They conveniently forget the innocent life he took—the one that still haunts Eleanor.
When a reckless midnight pursuit lands her in the path of danger, Needler finds her first. Eleanor escapes with her life, but something changes.
Needler has spared her, and now, she has his attention.
As the killer closes in, Eleanor is forced to confront the shadows of her city—and the chilling possibility that Needler might not be the monster she’s been chasing after all. He’s far more dangerous.
And he’s far too close.