The novel starts on a plane with, I think, two female characters boarding a commercial plane, I think either to or from Alaska. Something wrong happens (I don't remember if it was a "mechanical failure" or an outright attack such as via a missile) and one of the female characters is certain that they will die, so she tries to find a way to ensure the information she is carrying survives. Next, we cut to the actual protagonist, who is some sort of a mortician who works on military bases, helping to ensure that the damaged bodies that come in are made presentable for funerals. He recognizes the name of an incoming woman as someone he knew. As a girl, this woman was in a camping ground (Girl Scouts?) with his daughter. Somehow, a can (not certain if soda or aerosol) had wound up in the fire, and exploded, with this girl having tackled his daughter out of the way of the shrapnel. I believe there was some indication that the girl was neglected or abused at home, and he'd regretted that he never had the chance to really follow up on that before the girl left their lives.
Anyhow, in the process of preparing the body, he realizes that the women lacks the scar from the shrapnel from that can explosion, suggesting that this was someone else entirely. Either then or later, he also finds a piece of paper in the stomach, protected by the plane crash. After that, I don't remember the details other than that he finds the woman who'd supposedly died, who'd swapped her tickets with someone else who needed to get home earlier, telling them to convey the piece of paper, and when the plane went down, realized that she was a target and went underground, and that later, there's a scene on a base (Air Force?) where he discovers that a mentor of his is part of the conspiracy. I want to say that the conspiracy basically amounted to "losing" military supplies and weapons, and then selling them on the black market.
I think I read this as a paperback, maybe 5-6 years ago, which would put in in the mid-2010s. I don't remember if it was a new release at the time, but it didn't seem dreadfully old, either.