Rohan Rosewarne slammed his hand on a table in an audio-visual link suite at the Alexander Maconochie Centre and screamed at a lawyer during a NSW Coroner's Court inquest on Thursday.

After calling the lawyer a "demented c---", a "f---wit" and a "cocksucker", he switched off the connection to the court.

The dramatic scenes at the inquest, which is examining the February 2019 death of Charli Powell at Freebody Oval in Queanbeyan, left a seasoned coroner admitting she was "rattled".

On a tense day, Rosewarne, who is serving a 10-year jail sentence in the ACT over unrelated matters, grew increasingly aggressive as he spent several hours giving evidence.

He claimed that early on the morning of Charli's death, she left his Queanbeyan home in her pyjama pants after an argument about whether they were going to sleep on the floor or a "maggoty couch".

The prisoner said he believed his girlfriend was going to her mother's place to sleep before learning, during a subsequent phone call, that she was in fact in a toilet block threatening to end her life.

He claims to have found Charli, 17, in the wake of her having committed suicide in a toilet at the oval.

Jake Harris, counsel assisting the coroner, told the court on Thursday that members of Charli's family were "concerned about [Rosewarne's] involvement in her death".

Asked whether he had caused Charli's death, Rosewarne told Mr Harris: "Definitely not."

The inmate's frustrations reached greater heights under questioning from lawyer Michael Bartlett, who is representing Charli's mother.

Mr Bartlett suggested Rosewarne lacked respect for Charli, having saved her number in his phone under the name "slut".

Rosewarne denied lacking respect, saying he had probably done this in anger after one of his frequent arguments with Charli.

He had earlier said the pair "f---ed with each other's hearts" and that they had "toxic" disagreements, admitting some of his behaviour had been "f---ing putrid" but insisting it was "not one-way traffic".

Mr Bartlett, who has repeatedly said Rosewarne has "told inconsistent stories" about the morning of Charli's death, challenged the prisoner about whether he had offered up "a pack of lies".

Rosewarne denied this and said "I did not" in response to Mr Bartlett asking if he had killed Charli.

Quizzed on whether he had faked a suicide scene, Rosewarne said he had not, screamed "f---" and began pacing around the room from which he was being beamed into court.

After calling Mr Bartlett several names, he said Charli's family were not the only ones grieving and that he was "f---en hurting too".

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Rosewarne's supporters eventually got up and left the courtroom, calling out that they loved him.

One said "they're all dogs" as others began shouting at Charli's family and friends on their way out the door.

At this point, Rosewarne terminated the video connection.

Once Rosewarne and his supporters were gone, NSW deputy state coroner Harriet Grahame addressed Charli's loved ones.

"I don't really know what to say to you," Ms Grahame said.

"I feel rattled myself and I've been in courts for decades."

The coroner said she was looking forward to hearing about Charli and her "enormous spark" on Friday, when the teenager's family will have the opportunity to make a statement to the court.

Mr Harris and Mr Bartlett will then make written submissions for Ms Grahame to consider before the coroner delivers her findings.

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