A Cold Heart by Jonathan Kellerman

Juliet Kipper, a gifted painter, is strangled in the LA gallery where her first solo show has opened to critical acclaim, and Milo Sturgis takes on the murder investigation as a favour to an old friend. He consults Alex Delaware, who, researching parallels with other deaths, looks for artists killed when on the verge of a breakthrough or comeback. And he finds two others.

The investigation points to a gruesome, sadistic pattern of death, taking Milo and Alex into the dark side of the art world, and Alex’s ex-lover Robin into terrible danger.