Goodbye Sister Disco / James Patrick Hunt.

Enhanced descriptions from Syndetics:

Lieutenant George Hastings, a cool-headed, quick-thinking police detective, leapt to the forefront of the St. Louis Police Department when two beat cops were gunned down, and he led the joint FBI/police taskforce that caught the killer.

Now he is back at work with the FBI on a new case: Cordelia Penmark, the daughter of a wealthy businessman, has been kidnapped and her boyfriend callously executed outside of a posh holiday party for his law firm.
The murder was clearly a message--the kidnappers are willing to take this as far as they have to--and the target and the ransom demand indicate that the crime is politically motivated. But the investigators are stumped. Wary because of bruised egos on his team and bad blood among members of the young woman's family, and suspicious of the kidnappers' intentions, Hastings knows that there's more than simple politics in play as the kidnappers pull him and the girl's father into a deadly game of cat and mouse.
Slick, sharp, and authentic, "Goodbye Sister Disco," the sequel to the acclaimed novel "The Betrayers," establishes James Patrick Hunt as one of crime fiction's rising stars.