The Deductions of Neptune King

There is a serial killer on the loose murdering young, healthy male joggers in and around Battersea Park in this the 21st book in the Neptune King series. Neptune is dying to sink his teeth into the case, but his sister Mermaid insists he stay out of it as it is her husband's, John Griffiths case and she wants him to have the chance to do it without his help. John on the other hand swallows his pride and comes to Neptune for advice. He would rather accept Neptune's help than see another man murdered. Neptune undertakes his own investigation and passes on his findings to John, preferring to stay out of the limelight on this one. Meantime, Shark is working on another case, where a millionaire after a serious car accident is suddenly liquidating his assets. The millionaires brother believes he is being coerced because the new wife and butler won't let anyone in to see him, not even his own family. Shark soon confirms that the brother has cause for suspicion and with Neptune's help sets out to save the millionaire before all his assets are sold and he is murdered.