Forensic Investigative Genetic Genealogy testing will be used in the case of Mellory Manning whose body was found floating in the Avon River on 19 December 2008 and who was last seen alive the night before. Photo: Supplied
Police and the Institute of Environmental Science Research are trialling a DNA tool on two cold case murders in the hopes of solving them.
It includes the murder of Mellory Manning, who died after going to work on the evening of 18 December, 2008, and was last seen alive that night.
Her body was found floating in the Avon River in Christchurch early the next morning.
The second case is that of 6-year-old Alicia O'Reilly, who was found dead in her bed at her family home in Auckland's Avondale in August 1980.
Both families have been told about the developments.
Forensic Investigative Genetic Genealogy (FIGG) testing combines DNA testing with genealogical research to analyse genetic relationships between individuals who share small amounts of inherited DNA, with the crime scene samples.
The testing uses genealogy databases and publicly available records - something that is being used internationally to help solve cold cases and identify human remains.
Detective Superintendent Ross McKay said using techniques like this had the potential to provide investigative leads and potentially resolve unsolved crimes.
''This is a complex investigative tool and only cases where suitable DNA evidence has been captured during the criminal investigation would be considered, after all other investigative avenues have been considered and exhausted,'' he said.
To meet New Zealand conditions, all physical sample testing will be completed in New Zealand and extractions of the digital genetic code will be provided to a third-party international service providers, with no actual DNA material needing to be sent outside of New Zealand.
A staged approach to measuring success has been developed and an evaluation of the trial will be conducted at the conclusion of the use of FIGG for the two cold cases.