I like all the Jack Davis novels by Joel Goldman. I discovered them by accident. Jack Davis is an ex-FBI agent who was booted out of the FBI because he has a form of Tourette Syndrome. The author has the same condition. The main character teams up with an ex-cop to investigate murders.

Title: SHAKE DOWN: A JACK DAVIS NOVEL                                      

Author: GOLDMAN, JOEL                                     Original Date: 2008

Kansas City. At the scene of a drug-related quintuple murder, FBI    agent Jack Davis experiences the onset of debilitating tremors. Forced to take medical leave, Jack conducts his own investigation and, with help from jury consultant Kate Scranton, finds clues to his daughter’s disappearance. Strong language and some violence. 2008.  

DB   70011

Title: DEAD MAN: A JACK DAVIS NOVEL                                        

Author: GOLDMAN, JOEL                                     Original Date: 2009

Billionaire Milo Harper finances a neuroscience institute in which two brain research study participants die in the exact same ways they had dreamed about. Jack Davis, who retired from the FBI because of a movement disorder, tracks the killer. Some violence and some strong language. 2009.                                                         

 DB   70043   35