A familial search is when scientists search a DNA databank for close matches to an unidentified DNA profile from a crime scene. In New Zealand familial searches are conducted on behalf of Police by scientists from the Institute of Environmental Science and Research (ESR). They will search the DNA Profile Databank and the Temporary Databank for close matches to an unidentified DNA profile from a crime scene.
Any close matches found on these Databanks could be relatives of the owner of the unidentified DNA (who may be the offender). ESR lists these close matches in order of how likely it is that they will be a relative of the person with the unidentified DNA. Police officers can then decide whether to investigate the family members of the listed people.
A protocol between Police and ESR provides that familial searches will only be done in serious cases where there is no other evidence. ESR will only do this analysis when Police authorise it. Since 2008 familial searching has been conducted in 60 cases.
A number of high-profile crimes have been solved using familial searching – such as finding the killer of Marie Jamieson, who was killed in 2001.
In that case DNA from unidentified ‘Male A’ had been found at the scene of the crime but the police officers were unable to determine who it belonged to. In 2008, after they had exhausted all leads, Police authorised ESR scientists to carry out a familial search of the DNA Profile Databank. This search produced a ranked list of 49 individuals who were possible relatives of Male A.
Police officers investigated the highest ranked person on the list, ‘Ms B’, and found she had one brother, Joseph Reekers. After investigation police officers found sufficient evidence to link him to the crime. Reekers argued in Court that the police officers were not entitled to undertake a comparison between the Male A DNA and the DNA of his sister ‘Ms B’ stored on the DNA Profile Databank. However, the Court said it was permissible. This was the first time that the Courts in New Zealand allowed familial searching.
However, familial searching may not always produce helpful investigative leads. The story about Li Wei, Hemi and George in Case Two is based on a case from the United States where a potential suspect was identified through familial searching. In that case the police officers searched a genealogical database to see if there were any DNA profiles similar to the DNA found at the scene of an unsolved murder of a young woman. The police officers did find a similar DNA profile. They then began to investigate that person’s family members. They identified a relative who lived a long distance from the crime scene, but who was about the right age, made movies about murders, and had sisters who had gone to university in the same town as the murdered young woman. Based on this evidence, a police officer applied to the Court for a warrant for the suspect’s DNA to be taken. However, it turned out that his DNA did not match that of the killer.
(Unlike the United States, it should be noted that New Zealand Police have only ever conducted familial searching on the official criminal enforcement databases – the DNA Profile Databank and the Temporary Databank – not on genealogical databases).
Find out more about familial searching:
- The Washington Post, The ingenious and ‘dystopian’ DNA technique police used to hunt the ‘Golden State Killer’ suspect, 28 April 2018
- The Independent, Under the Microscope: How does familial DNA searching help solve crimes? 19 July 2010
- Washington Post, Police use DNA to solve 1976 murder of Karen Klaas, ex-wife of Righteous Brothers singer, 30 January 2017
- The New Orleans Advocate, New Orleans filmmaker cleared in cold-case murder; false positive highlights limitations of familial DNA searching, 12 March 2015
- Office of the Privacy Commissioner of Canada, A Family Affair: Forensic DNA Databases and Privacy Implications for Biological Relatives, 27 March 2015