It is Called 6* of separation : Cold Killer, and is about a Lead Agent in a fictional Unit of the FBI, called the MCU, who is going after a serial Killer that she thought dead 19 years before. Here is a sneak peak to anyone who wants a taste. This is a snippet from the first chapter:
“The body of a Marine was found last night,” Lockwood took a deep, shuddering breath, and opened a file that she didn't notice before. He took out a photo and held it up. The face of a pale male corpse filled her vision.
“This photo was taken by an an anonymous e-mailer, along with a set of coordinates, his rank and Military ID, and signed by the Initials CK. E-mail account and message was made from an untraceable server. No way to find out where it originated.” Lane rubbed the bridge of her nose, and internally swore as she felt the beginnings of a stress induced headache. It wasn't even 0900.
“I'm assuming you left the job of going to the crime scene to my team?” She asked, barely holding back a growl of frustration. Lane gestured towards the photo.
“And you didn't consider calling me last night, sir?” Lane raised her eyebrows and scoffed disbelievingly at the breach of protocol.
“The scene could be contaminated by now. The body could have been moved-” the black-haired woman scowled at the lack of concern in the Director's eyes. “You don't care.” She stated flatly. Lockwood shook his head.
“Agent Lane, we both know that the crime scene will stay intact. The Cold Killer always makes sure of that.” Lane winced as her headache gained traction and began to pound at her temples.
“Made.” she whispered, making Lockwood cock his head in question.
“Excuse me?” the brown-eyed man inquired, confusion heavy in his tone.
“Made,” Lane snapped, her voice filled with tension. “CK made sure, as in past tense, because this-” she gestured to the photo. Years of both her service in the US Army and as a federal agent made her feel only the slightest bit of discomfort at the sight of the photo. “Is not CK. It can't be, because I saw CK go into that building,” her voice had risen to a shout, and she knew that she was acting unlike herself, but this case, this killer… CK was one of her few triggers, guaranteed to make her pissed off. “I saw that building blow up, and I know that nobody survived it. So this? Is not him. It can't be. My team did not go through a year of hell for nothing. I did not tell the victim’s family's that they had closure because their loved one's killer was dead, only for that to be a lie! I did not lose-” she stopped herself before bringing up a subject they both didn't want to be brought up.
Lockwood had stayed silent during her rant eyes only flashing during her last words, and stayed so now that she finished, just gazing at her with calm eyes. Her gut clenched, and she sucked in a harsh breath, closing her eyes tightly.
“God, Darren. Please tell me it can't be him.” Lane all but begged. Lockwood only shook his head, giving her a sympathetic look.
“I'm sorry, Alex.”