Major advancements in DNA technology have helped convict a man over the sexual assault of a six-year-old Perth girl more than a decade ago.
Roland George Stayt, 49, committed the offence in January 2006 at a park in Medina, south of Perth.
But it was not until 2014 that Stayt was charged when a review of the case file led to a breakthrough.
Using advanced technology systems, police were able to extract a new DNA profile from the victim's clothing which was linked to Stayt.
The 49-year-old landscaper was arrested in July 2014 and charged with sexual penetration of a child under 13.
On Wednesday in the WA District Court Stayt was jailed for four years and six months. He pleaded not guilty, but a jury found him guilty of the offence following a trial late last year.
The court was told Stayt sexually assaulted the then six-year-old at the Medina park during a tee-ball game.
The girl had gone into a block of toilets to fill up a water bottle, where he assaulted her. Neither knew each other.
Police investigated the case at the time and tested the girl's underwear for DNA but could not find a match.
Police have confirmed the case was one of the very first unsolved sex offences to be re-investigated by a new WA police unit using new technology.
"This case was one of the first identified for re-examination under the (then) new program of review of unsolved historical serious crimes, initiated by WA Police in 2014," Acting Superintendent Peter Branchi said on Wednesday.
"Seeking to take advantage of the significant advancements in forensic technology in the period since the physical exhibits were originally examined in 2006, investigators submitted the material for further forensic analysis in 2014.
"As a result, a DNA profile was identified and matched to a profile on the WA DNA database.
"WA Police is committed to investigating historical unsolved serious crimes, no matter how old they are and will continue to utilise forensic technology as it evolves."
In a statement released to the media, the girl's mother said her "family was extremely grateful that justice had been served."
"When my daughter was assaulted all those years ago the police did everything they could to find the person but could not find him. So we tried to put it all behind us. Two years ago we were so shocked when the police (called) to say they had found the person," the mother said.
"Although the process was long and it took its toll on our whole family, we couldn't have asked for better support from everyone involved including child witness services, the prosecutor and the police. We are thankful that the police re-opened this case and the perpetrator is now in jail."
At Stayt's sentencing on Wednesday, the court heard he had previously been jailed for three years for child sex related offences in 2009.
He suffered a brain aneurism at the age of 18 and suffered from depression. The court was told he was a "low to average" risk of reoffending.
Judge Stephen Scott said sexual offences against children in the community were "alarmingly prevalent."
"The long-term effect on victims is considerable," he said.
"The community needs to be aware...that there is never any excuse for sexually abusing a child and those who act in this way and steal the innocence of children in a sexual manner will be properly punished.
"Children in our community should not be at risk in this way, when they are participating in activities in which they should surely be safe."
Stayt's four-year sentence was backdated to December 5, 2016 and he was made eligible for parole.