Showing Over the Edge by Jonathan Kellerman

Jamey Cadmus is clearly a deeply troubled young man. Found clutching a bloodied knife at the scene of a brutal double homicide, surely he must be the vicious serial killer who's been terrorising LA. What other explanation can there be? The public are demanding the death penalty but his lawyer is pleading diminished responsibility. Psychologist Alex Delaware is asked to make an assessment of Jamey's mental health but to do that he needs to look into Jamey's past and no one wants Alex digging there...