A relative of Craig Harman, jailed for killing lorry driver Michael Little, inadvertently led police to their man after officers used pioneering DNA techniques.
Craig Harman admitted manslaughter after giving DNA
DNA taken from a brick thrown through Mr Little's cab on the M3 was checked against the national database.
Using a new technique, 25 people with similar DNA were located and Harman's relative was top of the list.
Harman was then caught after giving a DNA sample which matched exactly.
Mr Little died in March 2003 as he drove his vehicle on the M3 in Surrey.
A brick crashed through his window after being thrown from a footbridge above the motorway, causing him to suffer a fatal heart attack.
On Monday, 20-year-old Craig Harman was jailed for six years for the crime.
Before throwing the brick, Harman had tried to hot wire a car after smashing the window.
Blood found in the Renault Clio, parked in a driveway in Brackendale Road, Camberley, matched DNA found on the brick in Mr Little's cab.
The DNA profile was checked against the national database, but because Harman did not have a criminal record no match came up.
It was then Surrey Police, with the Forensic Science Service, decided to use the intelligence-led DNA screening and familial searching.
Michael Little was praised by police for keeping his lorry under control
The technique, which is based on the fact that individuals who are related are more likely to have similar DNA, had been launched a few months before.
In July last year, a security guard pleaded guilty to murdering Cardiff prostitute Lynette White in 1988 after he was traced using the same technology.
South Wales Police arrested Jeffrey Gafoor from Llanharan, near Bridgend, more than a decade later after DNA evidence at the scene led to a close relative, and so to Gafoor.
In the same way, one of Harman's relatives was found to have similar DNA and soon the killer was tracked down.
A voluntary DNA sample from Harman was found to be a perfect match and in the face of the evidence he pleaded guilty to manslaughter.
Detective Chief Inspector Graham Hill, from Surrey Police, said: "There is no doubt in my mind that without this groundbreaking technique and the Forensic Science Service, this crime would have remained undetected."
The service will now be used by other police forces, who will have to pay £5,000 a time to the Forensic Science Service.