Let Her Fade by Blake Pierce

Fiona Red, a brilliant but quirky FBI loner, spends most of her time in the lab or at crime scenes. She comes from a family used to being around death and bodies, her parents having run a funeral parlor, and she would have run the family business if not for a tragedy in her past: her sister was abducted when she was a teenager, and never found.
Fiona remains determined to crack her sister’s case. But in the meantime, as an FBI agent, she applies her brilliance to catching killers and cracking cases that no one else can, as bugs are the first visitors to dead bodies.
With her FBI partner out in the field, Fiona expects to stay behind the scenes.
But Fiona, obsessed with catching killers, takes it one step too far, and may just find herself in the crosshairs of a killer herself.

A page-turning and harrowing crime thriller featuring a brilliant and tortured FBI agent, the Fiona Red series is a riveting mystery, packed with non-stop action, suspense, twists and turns, revelations, and driven by a breakneck pace that will keep you flipping pages late into the night.