‘Familial Searching’ – an explanation

“While the sins of the father should not be visited on the son, the sins of the son should not go unpunished because the sins of the father are ignored….”

We posted a poll on the website last week asking whether Familial DNA searching should be allowed in SA? [Familial Searching .i.e. a process by which an unidentified DNA profile is run through the state’s DNA data-bank looking not for an exact match but for a close match that would identify a family member of an unidentified perpetrator and could point in the direction of potential suspects.]

Notwithstanding the fact that only 2 people have voted so far, it has caused quite a lot of debate on Facebook! As such, I though that I should use this opportunity to open the debate further, as Familial Searching for criminal intelligence as well as the identification of unidentified bodies is being used in more and more countries throughout the world. It is however not without controversy, and whilst in some cases has been used to identify a previously unknown suspect of a violent crime, it has sparked some debate. This is not to say that the information presented here represents the views of The DNA Project – I am simply going to try and present the facts as objectively as possible and hopefully receive some constructive comment on the subject from some of you who read this blog.

In those countries where Familial Searching is allowed, it is important to remember that searches are only conducted on the National DNA Databanks which hold the profiles of previously convicted offenders, crime scene profiles and arrestees who have not yet been convicted.  Furthermore, a ‘hit’ when conducting a familial search,  does not mean that that person is the suspect – it is simply an investigative lead which may lead the police to the actual suspect who committed the crime. A DNA  Database for Criminal Intelligence is NOT a population database – in other words it is a database containing profiles of crime scene samples and convicted offenders & arrestees and not the general population. A familial search on a National DNA Database will therefore extend the size and reach of the DNA database to effectively include the parents, children and siblings of the offenders and arrestees whose DNA profiles are already stored in databases.

“Familial searching” is being used in some countries for efficient identification of possible crime suspects when traditional investigative efforts fail. Crime laboratories benefit from searching not just for perfect matches, but also for close ones, when trying to connect DNA from unsolved crimes to the DNA of known offenders whose DNA profiles are held in a national database. Because relatives share common DNA profiles, close matches can implicate family members as possible crime suspects.

As experience with familial searching increases, more and more countries will probably embrace the technique. And as they do, so does the need to create policies that will ensure both efficiency and accuracy in case selection, statistical thresholds and follow-up testing and investigation.

For those of you who would like to read more on the subject, the following report compiled by Sophie Rushton (July 2010) for the Australian & New Zealand Policing Advisory Agency looks at both the positive and negative aspect of Familial Searching and Predictive DNA Testing for Forensic Purposes: Report Familial Searching and Predictive DNA Testing 2010.

Case Solved – The Bloody Brick: Craig Harman

This was the first familial search in Great Britain in which the suspect was apprehended and convicted of the crime. In the early morning hours on March 21, 2003, Mr. Michael Little, a 53-year-old truck driver, was driving his truck on a highway in Surrey, when he drove beneath an overpass. A brick was thrown from the overpass and crashed through his windshield. It hit Mr. Little in his chest and caused fatal damage to the heart. Before Mr. Little died, he was able to bring his truck to a stop on the side of the road.

Michael Little

Law enforcement analyzed the blood on the brick and found two DNA profiles, one of Mr. Little and one of another unknown individual. That evening, before the brick was thrown from the overpass, a car had been burglarized in the same town. The burglar could not get the car started and he left his blood at the scene.

The police were able to extract a full DNA profile and it matched the DNA profile on the brick which killed Mr. Little. The profile was run through the DNA Database, but no match was found.

However, the DNA analysis established that the offender was caucasian. A police profiler looked at the details of the crime, and suggested that he was under the age of 35. Also, Surrey police believed the killer lived locally and so authorities performed a DNA dragnet screen involving 350 people from the surrounding area who volunteered to give samples. But still no match was found.

Law enforcement then decided to perform a familial search of white males under the age of 35 living in Surrey or Hampshire. Twenty five people with similar DNA were located including a relative of the suspect whose DNA matched 16 of 20 DNA markers. They interviewed the relative and discovered that he had a 19-year-old brother, Craig Harman, who lived where the crime had occurred. Harman gave his DNA voluntarily and confessed. In April, 2004, Craig Harman pleaded guilty to manslaughter and was sentenced to 6 years.

Case where Familial Searching was used in the USA: It was an unfinished slice of pizza that led to the identification of Lonnie David Franklin Jr. as the prime suspect in the Grim Sleeper murder investigation. But the pizza was just the final clue leading to his arrest. The key break in the investigation, intermittently conducted over 25 years, came when investigators found a close — but not perfect — match between the DNA recovered at multiple crime scenes and a man being held in a California prison. Such a near-match strongly indicated that the person wanted by police was a close relative of the man in prison, and police soon focused on the man’s father, Lonnie Franklin. They put him under surveillance, obtained his discarded pizza and found that his DNA matched that recovered at a Grim Sleeper crime scene.

Click here for more stories on cases solved by Familial Searching.


One Response to “‘Familial Searching’ – an explanation”

  1. F Jones says:

    Surely a national DNA database is required for familial searching to be useful?