Cold Streets by P.N. Elrod

It all starts with a kidnapping. A group of thugs kidnap the mentally handicapped daughter of a society matron, so Escott and Jack ride to the rescue. Jack uses his ability to ride along unseen in the vehicle that picks up the ransom money to track the kidnappers' gang back to the farmhouse where they are holding he girl, incapacitates the men, then hauls them off to the police station, hypnotized into giving full confessions, and takes the girl home to her mother. Joy all the way around.

Except that the ringleader of the kidnappers is a sociopath, and there are two categories of people upon whom Jack's hypnotic talents fail to work - drunks and crazies. So with the help of some sleazy lawyers and loyal friends, the leader, Dugan, gets bailed out of jail and appears to be on the road to acquital. Jack and Escott won't tolerate this, so a good deal of the novel is spent trying to send Dugan to jail instead of letting him expose Jack as a vampire - he wasn't hypnotized, and he remembers everything he saw.

On the gangland side of things, the bosses in New York are a little worried about revenues being down in Chicago, so they send one of their more brutal bosses, Hog Bristol, down to find out why, and to take over the territory from Gordy if he doesn't get satisfactory answers. Of course, Hog's a jerk, and nothing Gordy says will stop him from taking over Chicago. When either Hog or one of his men guns Gordy down in the street, Jack ends up taking over Gordy's operation temporarily to keep a New York takeover at bay.

It all ends up in a brutal scene after Jack is caught unaware by Bristol and his men, while he's chatting with a now captive Dugan. Again, I ask how in the world a vampire whose hearing is so acute he can eavesdrop on conversations across the room, and hear the changes in the heart rate of a blackjack dealer can let three goons get the drop on him. In the end, to escape the slaughterhouse where Bristol takes Jack to be tortured, Jack has to slip over the edge into madness for a time. We'll see in the next book if he's able to ever recover from his ordeal and what he had to do to survive.