Now that Michael Hegan, the former Belfast terrorist who got a new identity when he turned informer and then used his freedom to hold up a bank, is back in prison awaiting trial, he's an obvious target for murder--by the IRA mates he betrayed, the Brits angered by his light sentence, or anybody who might be interested in the ú2 million from the bank job. But Hegan is hale and hearty; it's his fellow prisoner Andy Heald, an inoffensive environmental activist convicted of bombing a fur shop, who's been found dead in his cell. Suicide and murder seem equally implausible, and in either case, how did whatever poison that killed Heald get smuggled inside? Those are the questions Inspector Jacko Jackson (Unfit to Plead, 1994, etc.) has supposedly been assigned to investigate. His assistants in the case--Sgt. Stan Young, Sgt. Frank (``Philippe'') Marlowe, and Constable Wayne Cross--don't know that his real job is to use Heald's death as a cover to find out which of them is the bent copper who knows where Hegan stashed the bank swag. Jackson himself, hamstrung by his reluctance to suspect a fellow officer, doesn't know that plans are already underway to spring Hegan in the event of an unfavorable verdict. Tough, smart, and crisply paced, with every twist perfectly judged: the most solidly packed British procedural you'll read this season.