Deep by C. N. Phillips

Sometimes what's done in the dark doesn't need to come to the light. It should stay shut away forever. The lifestyle of sisters Rhonnie and Ahli Drake is proof of that.
Born and raised in Omaha, Nebraska, Ronnie and Ahli have been raised to do the unthinkable to survive. With their father setting up all of their dangerous hits, the two have easily stolen over two hundred thousand dollars over the years. Still, they feel a void. They want to live normal lives while they still can.
Before they can perform their last job, which their father has promised will get them out of the game for good, a prior hit comes back to haunt them. It leaves their father with his throat slit and the girls in fear for their lives. With no money and no safe place to go, the girls have no choice but to agree to do one last hit.
What is supposed to be just a job turns into what will be the most horrific experience of their lives. Just when you think you know what's going to happen next, this twisted tale takes a deep dive for the worse.