Craig Rumsby murdered a teenage girl and attempted to rape another because of a sexual interest in females in their late teens and a tendency to act on it by committing opportunistic sexual violence, jurors have heard.
The similarities between both offences and his admissions to undercover police prove beyond reasonable doubt that the 56-year-old is guilty, crown prosecutor Lee Carr SC told the NSW Supreme Court in Dubbo on Tuesday.
Rumsby is accused of murdering 17-year-old Michelle Bright after she left a friend's 15th birthday party in Gulgong, central west NSW in the early hours of February 27, 1999.
Ms Bright's body was found three days later hidden in long grass on a roadside.
Her blouse had been pushed up, the clasps of her bra ripped off, and her jeans and underwear were around her ankles.
An autopsy of her body, which had grazes on the abdomen, thighs and knuckles, could not confirm the cause of death, with a report saying Ms Bright was killed by "homicidal violence of an undetermined aetiology".
Rumsby revealed to undercover police his knowledge of the crime that only the culprit would have had access to, Mr Carr said in his closing address.
He accurately described the type of underwear Ms Bright was wearing and recounted damaging her bra in a manner consistent with an expert examination, despite neither piece of information being available to the public.
"Was it just a lucky guess or was it somebody who was there," Mr Carr said.
"The Crown submits he knows it because he was there."
Rumsby is also accused of choking another female victim, who was then 18 years old, with the intent of raping her after she left a New Year's Eve party on January 1, 1998.
He pleaded not guilty to both charges.
NSW police had interviewed Rumsby since 1999 but did not arrest him until after the unsolved homicide team reopened the cold case in 2019.
In August 2020, police publicly announced a $1 million reward for anyone who had information about the murder.
Rumsby commented on a post about the announcement on the NSW Police Force's Facebook page.
"It's so sad they haven't caught her killer yet. Michelle was like a sister to me. I feel sorry for her," he wrote.
Mr Carr said the comments were Rumsby's way of "putting up a facade" to distance himself from the crime.
"It's just smoke and mirrors," he told the jury.
"And that's the way you should treat it."
While there was no physical evidence connecting Rumsby to the murder of Ms Bright, his wallet was found at the scene of the 18-year-old's alleged attempted rape.
The jury heard that alleged victim, who cannot be named, did not press charges and retracted a statement made at the time as she feared going to court and having her character discredited.
Rumsby told the undercover officers he tackled her because she was "a good sort" and he "wanted to have a bit of a crack".
"That is a stated intention of what somebody wanted to do," Mr Carr said.
The alleged victim earlier told the jury of how the man emerged from the shadows, hit her and grabbed her throat, then pushed her onto the ground and got on top of her, threatening her to shut up or he'd kill her.
The man fled after her boyfriend emerged from the house and threatened to hit him with a concrete manhole cover found nearby.
Mr Carr detailed the similarities between the ambush and that of Ms Bright, who was also grabbed by the throat late at night, in a sexually motivated assault, while alone, in a dark place.
It would be "extraordinary in the extreme" to assume they were committed by different assailants by sheer coincidence, the prosecutor said.
The defence will deliver its closing address on Wednesday.
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