The dance master

When Matthew Hopkins leaves his hell-hole council flat to seek out funding for his heroin addiction, he spots a plastic bag on the landing outside. Pouncing on it hopefully, he finds it contains only bones. It would seem the killer wanted to draw attention to himself, perhaps even to be caught. But when a new urgency infuses the case, will Hennessey and Yellich be able to make use of his helpfulness in time?