Vance And Shepherd Mysteries - Books 1-4

The first four books in 'Vance And Shepherd Mysteries', a series of crime mystery novels by John Broughton, now in one volume!
The Quasimodo Killings: Detective Inspector Jacob Vance and Detective Sergeant Brittany Shepherd are called upon to prevent a series of murders across London. The Metropolitan Police Commissioner has provoked a psychopath with her inaugural speech and soon later, receives a letter threatening a series of nine killings. With time running out, can the detectives capture the perpetrator and prevent him from killing again?
The London Tram Murders: After a murder is committed in a quiet suburban subway under a tramline, it becomes clear that the squad is dealing with a copycat killer. The murder is an uncanny repeat of their previous case, and their inquiries are complicated by the presence of the main suspect's doppelganger, Melanie Bradshaw. As the killings continue, Vance and Shepherd face increasing pressure from above building. Can they apprehend and bring the killer to justice?
The Thames Crossbow Murders: After a crossbow bolt kills a birdwatcher in a remote site on the Thames, the Metropolitan Police discover they have another serial killer on their hands. Soon after, a virtuoso pianist loses his life in the same manner. The murders are all connected to the river Thames, but the waters are muddied by the involvement of British and Russian secret services. What do the international organizations have to do with the case, and who is the killer?
The Thames-Tigris Connection: Vance and Shepherd are investigating a case in Central London. Murders of prominent Iranian exiles present Vance with a powder-keg primed to explode. He and Shepherd must avoid a conflict among London's Muslim community. MI-6 involvement results in the closure of three unsolved cases, but the Intelligence Agency has a plan for Shepherd and her abilities. But can they discover and take down the fanatical anti-Zoroastrian movement and provide justice to the victims of the closed cases?