Police allege the boy was riding his bike through the Carine Open Space, in Perth’s north, when he was confronted by a man who restrained him then sexually assaulted him.

Detectives used new investigative techniques in genetic genealogy, as well as traditional police work, for their investigation.

Special Crime Squad Detective Superintendent Rohan Ingles said they had been able to bring more historical cases before the courts using the technology.

“Forensic evidence from the scene led to the Investigative Genealogy Team becoming involved in the case in early 2024, leading to a family tree of nearly 3500 people being compiled,” Mr Ingles said.

“With methodical hard work, the IGG team narrowed down the sample leading to the Special Crime – Homicide team conducting further inquiries and arresting the man for a crime he allegedly committed over 30 years ago.”

A Kinglsey man has been charged with deprivation of liberty and two counts of aggravated sexual assault.

He faced Perth Magistrates Court on Tuesday, with Magistrate Tom Hall saying the incident was one of the worst he had heard.

The man was refused bail and is due to reappear in court in July.