Abuse survivor Grace Tame has told a Tasmanian court that she feared for her life following tweets made by the man who sexually abused her as a child.

Nicolaas Ockert Bester, now in his mid-70s, was charged with three counts of using a carriage service to menace, harass or cause offence in relation to three public posts in 2022 on Twitter, now X.

In 2011 Bester was jailed for sexually abusing Ms Tame. At the time of the crime, he was a school teacher and Ms Tame was a 15-year-old student.

In February he was found unfit to stand trial due to medical reasons.

"The findings are not guilty, not guilty on grounds of insanity or a finding to the same effect … or a finding cannot be made that the defendant is not guilty," prosecutor Ruth Champion told the court during a special hearing on Tuesday.

The tweets referenced a countdown to a "comeuppance", which Ms Tame told the Hobart Magistrates Court coincided with the release of her memoir.

@nicobester3 April 27 2022 — great news! Twitter at last been crunched, liberated by Elon Musk. At last I shall come for [email address] … in good time…

@nicobester3 July 21 2022 — bring back Donald trump, bring back tommy Robinson, I want to see milo Yiannopoulos, nico bester is coming too…oh yes he is…only 10 weeks to go, [email address] , he is coming to show all to you

@nicobester3 Aug 28 2022 — here it comes! Only 4 weeks to go!! The good old comeuppance on its way…[email address]

The tweets included Ms Tame's childhood email address, which the court heard was connected to her old Facebook account, via which Bester and Ms Tame communicated at the time of the abuse.

She described fearing for her life after seeing the tweets.

"Aside from re-traumatising me … it destabilised me, made me convinced that something was going to eventuate. I feared for any number of possibilities, public humiliation or indeed, death," Ms Tame said.

"I was unsure of how this might play out … I took comeuppance to mean revenge.

"I got pretty close to rock bottom again."

She said her publisher and touring company added extra security to her book tour events in response to the tweets.

"This is a man who has psychologically tortured and raped me. I do not need to imagine his capacity to cause harm," Ms Tame told the court.

Speaking outside court after the hearing, Ms Tame said the latest events had been incredibly difficult on her and her loved ones.

"This is over half my lifetime that this has taken up, and like many survivors of child sexual abuse, the impacts of that trauma have been profound and long-lasting," she said.

Document sent to Bettina Arndt, court hears

Ms Tame, an Australian of the Year recipient, told the court she began to worry that Bester would share messages from the time of the abuse.

"They led me to suspect that this 'comeuppance' may involve public dissemination of content from that time … content in which we conversed during a time that this man groomed and coerced me into believing and saying things that weren't true," she said.

Ms Tame said she reported the first tweet to police in May 2022.

"Content that made reference to my own experience of child sexual abuse at [the] hands of this man," she said.

"I wasn't sure if coming from him, it often had very specific detail that I believed could only have come from him."

Ms Tame told the court she feared for her safety.

"During the abuse in 2010 and prior to that in 2009, I recall anecdotes he would share from his time in combat. He had shared with me he had killed people," she said.

Lead police investigator Detective Senior Constable Declan Gilette gave evidence that during a search of Bester's residence in October 2022, police found a document which appeared, "to contain extracts from Facebook messenger".

"Predominantly messages sent by Grace Tame to Bester, pasted into this document in different sorts of formatting over time," he said.

Senior Constable Gilette said this document was saved with the file name "additional material for Bettina" and emailed to social commentator Bettina Arndt.

The court heard Ms Arndt interviewed Bester in a 2017 video titled Feminists persecute disgraced teacher.

The document was also found in a folder on Bester's devices, titled "Wraak".

Senior Constable Gilette told the court he believed Bester had served in the South African army, and "wraak" was Afrikaans for "a noun meaning revenge or vengeance".

The matter will return to court in December.