Cheating at solitaire : a Gregor Demarkian novel / Jane Haddam.

Enhanced descriptions from Syndetics:

Margaret's Harbor, a small, exclusive island off the coast of Massachussets, has been disrupted for weeks by the antics of a group of young celebrities. Kendra Rhode, of the extremely wealthy Rhode family, is the ring leader and part-year resident on the island. Two of her cohorts, Arrow Normand, an aging teen pop idol, and Marcey Mandret, another of the same vintage, have been acting out publicly - drunken, disorderly public behavior eaten up by the press. During one of the most devastating blizzards in decades, Normand staggers up to a local house, covered in blood and incoherently drunk. Her latest boy toy is found shot dead in the front seat of a crashed truck. The only suspect in the crime is Normand herself and she was apparently far too out of it to remember what actually happened that night.    Former F.B.I. agent Gregor Demarkian, fleeing from the preparations for his own wedding, is hired to review the case against Normand. What he finds is a case with little evidence, twisted by an out-of-control media and the cult of celebrity surrounding the three young women, and a mare's nest of motives, in what may be the most confusing, twisted case of his entire career.