Angel of Mercy - Andrew Neiderman

A police detective confronts a nurse with an unusual bedside manner and her chilling twin sister in Andrew Neiderman's page-turning thriller

Palm Springs detective Frankie Samuels is on medical leave when a rash of suspicious suicides rock his town. Against the advice of his doctor and his supervisor, he investigates the case of a grieving widower who died of insulin shock, overdosing on his wife's meds, along with a sleep aid called Dilantin. But the police can't find any Dilantin in the man's medicine cabinet. The second victim, another surviving spouse, perishes from a lethal dose of chloral hydrate.

Private-duty nurse Faye Sullivan seems to be the common denominator in the deaths. But Faye has a sister: an identical twin named Susie, who also has a connection to the victims. As Samuels discovers more clues that don't add up, his suspicion begins to fall decisively on the two women. But the truth is more terrifying—and deadly—than he can imagine.