Police in Western Australia have laid charges in two separate, decade-old cases thanks to enhanced DNA analysis techniques.
In separate statements issued on Tuesday, Western Australia police said they had laid charges in a sexual assault case dating back to 2014 and an unrelated commercial burglary in 2012. In both instances, they said they had used enhanced DNA forensic techniques as part of a review of the investigation.
The force said it had charged a 36-year-old man with “sexual penetration without consent” as part of an investigation into an alleged incident in Jurien Bay, 220km north of Perth, in December 2014.
It is alleged a woman aged in her 30s was followed into the bathroom of a hotel and sexually assaulted by the man, then 27 years old.
Police said at the time of the incident a male suspect was identified, however, there was insufficient evidence to charge him.
The now 36-year-old man had been charged after a full review of the case was conducted using “enhanced DNA forensic techniques to analyse items of evidence seized at the time of the incident”, according to a WA police media statement.
In an unrelated case, WA police said on Tuesday they had charged a man over a commercial burglary in December 2012 in the Perth suburb of Morley.
It will be alleged copper wire, copper cutoffs, a copper cable winding machine and other items worth more than $70,000 in total was stolen.
Police said in a separate media statement that they had conducted a full review of all aspects of the investigation and used enhanced DNA forensic techniques to analyse items of evidence seized at the time of the burglary.
A 59-year-old man, who was 48 at the time of the incident, had been charged with “burglary and commit offence in place” and “stealing”.
‘We can analyse things that you could not have analysed before’
Significant advancements in the sensitivity of DNA testing have been made in the last 10 years, according to a spokesperson from Independent Forensic Services, an independent company that does forensic and DNA analysis.
“They are testing much smaller amounts of DNA, they are much more sensitive,” the spokesperson said.
“So you are going to get DNA results from samples we previously wouldn’t have been able to obtain DNA results from, and then you are also going to be able to interpret DNA results that you previously wouldn’t have been able to do as well.”
Speaking generally and not about the two active cases, Prof Adrian Linacre, the chair in forensic DNA technology at Flinders University, said “tiny traces” on things touched, even briefly up to 20 years ago, had enough DNA to “now generate a result that we couldn’t before”. That can include door handles, pyjamas and the handle of a knife.
The improved technology had not been a massive jump, but instead a series of “impressive improvements”, Linacre said.
Around 2014 to 2016, a new software program STRmix was developed by scientists in Australia and New Zealand that allowed the interpretation of more complex DNA profiles.
Since the late 90s, crime scene items have been seized with care – “they are correctly sealed and labelled and packaged,” Linacre said. “They have been well packaged with the hope that technology will improve.
“We can analyse things that you could not have analysed before,” he said. “Now as technology has improved … there comes a point in cold cases where you think let’s try and analyse now, given what we can do.”
