Both women testified in court about the allegations but only one got the verdict she was hoping for.
One charge, that Beamsley was found not guilty of, related to one victim and the other five charges related to the second victim.
The first victim said when she was just three-years-old Beamsley, who was nine years older, started to do "sexual things that assimilated to sex".
"He would remove my underwear and rub his genital on mine. When [he] had decided he had fulfilled his urge he would get up," she told the court.
Crown prosecutor Chris Wilkinson-Smith said Beamsley would use babysitting as an opportunity to sexually assault her.
"When she was 7-years-old she recalled a chilling incident when she was called into David's motorbike garage.
"She knows she was lying on cold concrete, hanging onto her underwear and her heart is bumping," Mr Wilkinson-Smith said.
The victim said Beamsley had told her it was their secret and "if you tell you won't be believed. You'll be the bad person and you'll be taken away from mum and dad and you'll never see them again".
Mr Wilkinson-Smith said she hit breaking point when her younger sister was born and she wanted to protect her from the same abuse.
"She told her brother, things blew up and Beamsley was thrown out of the house."
But defence lawyer Debbie Goodlet questioned the victim's recollection of the events and suggested the abuse never happened.
"Apart from the sequence of these events and where they occurred you have no memory time-wise or age-wise of when those first two events occurred?
"I suggest that perhaps your memory and recollection are unreliable."
The jury decided there wasn't enough evidence to find Beamsley guilty of these allegations.
However, second victim did get the justice she was hoping for.
On Tuesday, she told the court of seven occasions when David Beamsley sexually assaulted her when she was a child.
She said Beamsley offered to take her for a drive to give her separated parents some time alone.
"He asked if I wanted to help my parents get back together, while rubbing my leg back and forth. I felt uncomfortable but I was seven at the time and confused."
She said when she got upset Beamsley would soothe her and tell her he would get her a treat from the dairy.
"He told me to count to 50 until it was over and I just closed my eyes and zoned out.
"He said if I told my parents he would hurt them, shoot them while they were asleep in their bed."
She laid five charges against Beamsley and four of them he was found guilty for.
The charge he was found not guilty to related to a family gathering when Beamsley allegedly touched her vagina and bottom.
Before the jury went into deliberation at 3.45pm on Thursday, the judge warned the jury to tread with caution because it was 34 years ago when the first victim's offending were alleged to have occurred, and 37 years since the second alleged offences.
