Warning Signs by Stephen White
I enjoyed reading this novel, although I was distracted by some other issues at the time so probably didn’t get into it as much as it deserved 
The action takes place in Boulder, Colorado, where the murder of a district attorney is just the beginning of a terrifying trail of violence.
Indeed, the possibilities of terror within the book are very real and all too plausible, as is the human frailty we see in some of the major characters, particular the hero and part-time narrator Alan Gregory, the clinical pyschologist who has featured in a number of Stephen White novels, and homicide detective Lucy Tanner, a suspect in the first half and a victim in the second half of the novel, with some very human failings despite having some likeable features. The real villain of the piece is also ambiguous in that we cannot really blame his motivation even as we abhor his methods! This book is well worth a read as are other books by Stephen White!
Speaking of Stephens, I am currently half way through Stephen King’s Cell and I will be posting my review of it in the next few days!