According to police, suspected child molester was caught after 33 years using the family tree method

Australian police said they arrested a suspected child rapist this week after nearly 33 years, thanks to “groundbreaking” investigative techniques that used the suspect’s DNA to create a family tree.

Gavin Jeffery Durbridge, 54, appeared in court on Tuesday charged with false imprisonment and two counts of aggravated sexual assault. The incident allegedly occurred in 1991 when a 13-year-old boy was attacked, WAtoday reports. Durbridge had been arrested a day earlier in connection with the incident. The judge described the details as the worst he had ever heard.

The alleged assault occurred on October 25, 1991, as the boy was riding his bicycle through the Carine Open Space – a park and recreation area in a suburb of Perth, Western Australia. Authorities say the boy – who has not been named – was on his way to a friend’s house when he was attacked by a man who allegedly threatened the child with a knife before restraining and attacking him.

According to reports, the boy immediately informed the police about the incident and a swab was taken from his clothes, which had been kept for 33 years.

“New investigative techniques based on genetic genealogy coupled with good old-fashioned detective work have led to the result we have today,” said Chloe White of the Western Australia Police of the process that led to Durbridge’s arrest.

She added that an Investigative Genetic Genealogy (IGG) team “was involved in this case earlier this year and their research led to the identification of a family tree of nearly three and a half thousand individuals.” “Hard work led to this day when the team arrested the man,” she added, saying the alleged victim was “delighted” with the outcome of the investigation.

Although police did not provide a detailed description of what led police to Durbridge, IGG involves identifying suspects by comparing DNA samples collected at crime scenes with the genetic information in genealogical databases. If investigators find even distant relatives, they can use other sources of information, such as birth and marriage records, to build a family tree that can ultimately be used to identify possible suspects.

Such techniques were famously used to catch Joseph James DeAngelo, the so-called Golden State Killer, who pleaded guilty in 2020 to a series of murders and kidnappings in California in the 1970s and 1980s.