The Man Downstairs

From publisher blurb: The tenants at 224 Lenox Avenue, between W 121st and W122nd, New York City, have a neighbor they have never met, and never knew existed until a few weeks ago, yet he has always been there. Josef Voorzanger has been hiding for more than forty years, but time has eaten his once-sharp mind, and his wards are no longer strong enough to keep out the curious. Josef made a bad bargain a long time ago, and now the entity he bartered with is sending the Man with Lightning Flowers to collect - unless the investigators, hired by the owners of 224 Lenox, can find Josef first.