No Trace by Jim Crigler

The nicest people live in the suburbs. The nicest people commit murder. When a mathematician is killed in his home in the sleepy Atlanta suburb of Bristow, detective John Mason is perplexed by two things: the near total absence of any forensic evidence at the scene, and the hush-hush interest that the FBI has taken in the crime. When Mason traces the FBI's interest to his former employer, a small, now-defunct defense contractor, he enlists the aid of his friend, Ron Penfield, to work out what's going on. After all, Ron helped solve a couple of previous cases, and he worked with Mason at the defense company. But Ron's past, both recent and remote, is about to bowl him over and leave him traumatized and unable to help. And Mason is about to face up to ghosts from his own past, as well.