The Paraffin Glove And The Dark Genius

In the first story, The Paraffin Glove, Detectives Fisher and Goldstein investigate the murders of two male individuals and another practically on life support. The two detectives are unable to come up with any clues how the two were murdered or even why. They find themselves following a very dark and suspicious man.
In the second story, The Dark Genius, one of the detectives feels as though they might have a stalker. Nothing could prepare one of the detectives for what they will experience and the person behind it all. In The Dark Genius, two of the detectives and their captain must consider that they might be looking for a serial rapist.
In the Dark Genius, Detective Jackson and Captain Costello are called to a crime scene where the remains of a female are left, and the crime scene reminds Captain Costello of a case he worked on just a few years earlier with Detective Fisher and the FBI.