The 25-year-old son of former senator and NSW premier Kristina Keneally had recently chalked up two years in uniform and was manning the desk at Newtown police station when Luke Brett Moore called in February 2021.
Keneally's written statement, which he said he felt "pressured" to make after answering the phone and talking to higher-ranking officers, resulted in Mr Moore being arrested and held in custody for three weeks.
It contains what Keneally eventually acknowledged in cross-examination in Downing Centre Local Court on Tuesday were "significant" discrepancies against an audio recording Mr Moore took.
Significant differences included Keneally naming a police officer he alleged Mr Moore threatened to kill.
Crown prosecutor Daniel Boyle, who suggested the differences and discrepancies were "significant" at least three times before Keneally accepted that description, said the statement and recording were "not even close".
Mr Moore does not name the officer or threaten any violence against them in the recording.
Keneally quotes a conversation including questions he never asked and answers Mr Moore never gave in the statement that led to the constable being charged with fabricating evidence with the intent of misleading a judicial tribunal.
"I can't recall exactly but that was my recollection of the conversation at the time I wrote that statement," Keneally said in answer to one question on Tuesday, using words to that effect for several others.
Keneally incorrectly said he had asked Mr Moore what he meant when he said he wanted a detective "off the planet" and claimed Mr Moore said "good as gone" and "dead".
Keneally's lawyer Paul McGirr contends his memory was affected by a combination of stress, fatigue, and contamination from other sources including fellow officers and Mr Moore's website isuepolice.com, which Keneally visited while on the phone with Mr Moore.
He also looked up Mr Moore's details in the police system, but did not listen to every word of the 12-minute phone call, or take contemporaneous notes of it.
The young constable was directed to make the statement, did not know what it would be used for and was doing his best, but made a mistake, Mr McGirr submitted.
An expert who watched Keneally give evidence told the court how dividing attention between multiple sources could affect recall even hours later.
"It means the information that's encoded form any of those sources is less ... so deciding later on where particular information is coming from, it's more difficult," Deakin University psychology senior lecturer Stefanie Sharman said on Tuesday.
Mr Boyle said Keneally used direct, detailed quotes and did not express any uncertainty about them.
"This was not a mistake," he said.
Mr McGirr said Keneally introduced the quotes by saying "to the best of my knowledge the following conversation occurred," and were not things he had "plucked from the air".
While it was conceded Keneally's evidence was incorrect the prosecution did not prove he fabricated it with the intent of misleading judicial proceedings as charged, and had offered no real motive for him to have done so, Mr McGirr said.
Mr Boyle said Magistrate Rodney Brender would "comfortably infer" Keneally "made this up ... and that he had the relevant intent".
The court adjourned for a decision on November 21.