China Lake: An Evan Delaney Novel (Evan Delaney, Book 1) (Unabridged‪)‬

Evan Delaney is shocked to learn that her ex-sister-in-law, Tabitha, has joined the Remnant, a religion with a dangerous and fanatical following.
What is more alarming is that the unstable young mother plans to regain custody of her son and disappear with him into the fold of the church. She has the Remnant on her side, and they'll do anything it takes - including murder - to get what they want.

But it's another member of the Remnant who's killed, and when Evan's brother becomes a suspect, Evan is dragged even deeper into the nightmare.