Four Blind Mice (Alex Cross)

Detective Alex Cross is on his way to resign from the Washington, D.C., Police Force when his partner shows up at his door with a case he can't refuse. One of John Sampson's oldest friends, from their days together in Vietnam, has been arrested for murder. Worse yet, he is subject to the iron hand of the United States Army. The evidence against him is strong enough to send him to the gas chamber.
Sampson is certain his friend has been framed, and Alex's investigation turns up evidence overlooked - or concealed - by the military authorities. Drawing on their years of street training and an almost telepathic mutual trust, Cross and Sampson go deep behind military lines to confront the most ruthless - and deadliest - killers they have ever encountered. Behind these three highly skilled killing machines there appears to be an even more threatening controller. Discovering the identity of this lethal genius will prove to be Cross's most terrifying challenge ever.
On his visits home, Alex must confront another, more disturbing mystery: what's the matter with Nana Mama? As he explores the possibility of a relationship with a woman who offers him new hope, Alex must also face the fact that his beloved grandmother is only human.