A family friend accused of molesting two sisters "took fleeting opportunities" to gratify his sexual interest in the children, a prosecutor has told a jury.
During her closing address in the ACT Supreme Court on Friday, prosecutor Greta Cuthel said the "persona [the accused] projected outwards to the family was very different to the man he was inside".
The trial of the now 30-year-old man, who cannot be named for legal reasons, began last week.
He is accused of indecently assaulting the girls, with the youngest aged six or seven at the start of the alleged crimes, spanning several years dating back to 2011.
The man has pleaded not guilty to four counts of committing an act of indecency on a young person, four counts of committing an act of indecency without consent, and one count of sexual assault in the third degree.
In his closing address to jurors, defence barrister Keegan Lee said they "would have some questions and concerns about the reliability of the allegations".
"It doesn't make sense," he said.
"No one else saw them despite being in rooms next door and things happening in front of people."
Mr Lee asked the jury to "consider the unlikelihood of the allegations occurring in the way or the circumstances described".
He said there were inconsistencies in the alleged victims' evidence to the court.
Ms Cuthel said "the reality from all of the evidence is that both girls were sisters unaware that the accused had assaulted [the other]."
"The accused was a trusted member in the families, they were not looking at him suspecting wrongdoing," she told the jury.
"No one knew what the accused got up to when he was relatively alone with the sisters."
The prosecutor read from a journal entry the younger sister wrote several years after the alleged indecent assault.
"After years of suppressing my experience it was brought back by seeing him at a party," the journal read.
"The flashbacks were too real and I can remember what it felt like ... and all the shame
"I didn't think anyone would believe me."
The accused denies the allegations.
The man, who was the son of family friends, is accused of touching the girls' genitals and kissing them when they visited his house.
It is alleged that he asked the youngest girl to sit on his lap when she was aged six or seven, before touching her arms, kissing her and rubbing her genitals.
The man is also accused of indecently assaulting and sexually assaulting the older sister, starting when she was aged 14 or 16.
One of the allegations involved the accused grabbing the older girl, pulling her into his bedroom, pushing her down on a bed and trying to kiss her.
He also allegedly touched the older girl's bottom multiple times during a family party when she was aged between 15 and 16.
The trial continues.
