The Brain Vault by Lawrence Kelter

A sterilized skull, a deranged forensics expert, a plunge into the deepest recesses of the criminal mind. In her most challenging case yet, Chalice must turn to a madman to deliver a killer. Detective Chalice is called into action when a unconscious man is found in Central Park. Barely alive, John Doe is clad only in a torn bed sheet and has sustained a life threatening wound. His body is covered in scars, essentially a tapestry chronicling his history as a torture victim. Stranger still, a human skull lies just inches away. Chalice has just two leads in this case, a skull that has been sterilized and found to be evidence free, and an comatose witness to a murder—tough odds, even for NYPD’s best and brightest.