Dead Skin

After a recent promotion to Inspector in the Queensland Police Service, Helena Costa investigates two Brisbane murders, but the crime scenes lack vital clues. Under pressure from her superior officers to apprehend a suspect, she requests help from Dr Mark Altree. He is a geologist and amateur sleuth who solved Costa's mysterious missing person case. Altree visits the murder scenes and reviews the files, but the lack of evidence frustrates his attempt to solve the crimes. Without making an arrest another brutal slaying leads to Costa's demotion and transfer from Homicide to the Road Policing Unit. Determined to find the serial killer Costa persuades Altree to continue with her clandestine murder investigation. In addition to their usual mineral exploration activities, Altree, his wife Sonja and their colleague Daniel Hawkes conduct research into the crimes.

Hawkes skilfully vacuums the floors of the crime scenes and examines the filters containing strands of hair and dead skin cells. Altree draws on a favour from a university colleague to analyse the chemical compositions of the dead skin cells. The analyses and nature of the dead skin cells indicate a person with psoriasis was at all crime scenes. Sonja carries out family history research, approaches several possible suspects and collects vital evidence from a wrecked car. Her genealogical and digitised newspaper research also reveals a family dispute between James Killoran and his first cousin James Nikolai, alias Nicholas James, two prime suspects.

Costa and Hawkes develop a relationship whereas Altree's autocratic leadership sparks tension with Sonja. Costa's team of amateur detectives narrow the suspects to James Killoran, the fiancé of a murder victim; Thomas Stirling, the son-in-law of another victim; and James Nikolai, the financial adviser to all victims.

Altree's astute observations and creative thinking leads to the discovery of the murder weapon and of the plot by Killoran to frame his cousin. Costa uses forensic information, the discovery of the stolen property, evidence of fraudulent activity, and his psoriasis to name Killoran as the serial killer. Based on the results of her surreptitious activities, Costa's boss issues a warrant to arrest James Killoran. Before the warrant is enforced James Nikolai shoots Killoran to settle the family feud.