Snifter of Death. The Bloodstone Series, #2

The summer of 1889 was proving to be a strange one for Detective Inspector Rudyard Bloodstone and his partner. They had a sexual pervert loose. The man didn't actually harm women but threatened them at knife point, fondling them, and ultimately stealing their stockings. Far more serious were the murders of influential men, which appeared random other than they were all killed by arsenic poison. Never had he and his partner had cases with so little workable evidence.
Also, the rivalry between him and his detective nemesis at London's other police department was intensifying. That nemesis was the boxing champion of their department and looking to challenge Rudyard, who never trained as a boxer. Besides Rudyard's pride being at stake, and the pride of his station, his nemesis also had in his possession a scandalous photograph of the woman Rudyard cares very much for.
The new lady in Rudyard's life had captured his heart and he'd fight the devil himself to save her reputation.