Playing with fire

Summary: A blaze consumes two rotting barges moored in a Yorkshire canal, killing their squatter inhabitants--Tina Aspern, a pretty, teenage heroin abuser, and Thomas McMahon, a once-promising but "derivative" landscape painter who'd fallen on hard times. Accident or arson? The best suspects, in either event, may be Tina's cheating boyfriend, Mark Siddons, and a rumored peeping tom who'd taken his time--and more--reporting the conflagration. However, as Detective Chief Inspector Alan Banks and his colleague and ex-lover, Annie Cabbot, gather together the disparate threads of this case, new questions arise, suggesting that the inferno was intended to cover up still worse misdeeds. Why, for instance, had McMahon been buying old books and prints from an Eastvale antiquarian dealer? Is it true, as an angry Siddons alleges, that Tina had turned to drugs in order to blot out the pain of her stepfather's carnal advances? And what tie, if any, is there between these boat burnings and the subsequent torching of a trailer home occupied by a "quiet bloke," who perished while in possession of an unknown and potentially valuable J.M.W. Turner watercolor?