Details of last year's assault were revealed in documents tendered to the ACT Supreme Court on Friday, when one home invader faced a sentence hearing.

That man, Bailey Hagen, has pleaded guilty to charges of aggravated burglary and joint commission assault occasioning actual bodily harm over the July 2021 incident.

Agreed facts show he, a child and three women, including his mother Trinity Lee Hagen, went to the victim's Hawker home about 2am on the day in question.

The victim, convicted arsonist Samantha Chatfield, had previously been in a relationship with another Hagen who was remanded in custody at the time.

That person, Jordan Hagen, emailed new partner Mikaela Engeler about 90 minutes before the offending and urged her to retrieve his "shit" from Chatfield.

"KICK THE F---ING DOOR IN," part of one message read.

The agreed facts say that when the group turned up at Chatfield's home, Bailey Hagen went into the apartment with the child and asked for "my brother's shit".

Chatfield told them to get out but they did not, and she was dragged out the front door to the verandah by Engeler.

There, Engeler and co-offender Rebecca Eade punched and kicked Chatfield, according to the agreed facts, striking parts of the body that included the head.

Bailey Hagen picked up a large knife or machete at some point, assisting in the assault by standing nearby and preventing Chatfield's brother from stopping it.

During the assault, which involved Engeler burning Chatfield's hair, Trinity Hagen went into the victim's bedroom and started packing items into a bag.

She eventually left with "several bags of items", the agreed facts state.

A neighbour called triple zero to report the incident, and Chatfield was later found to have cuts to her right torso and right hand, singed hair, and welts on her forehead and neck.

Soon after the incident, Trinity Hagen emailed son Jordan to say she had not long got back from the home of "that evil fkn slut ex of urs [sic]".

"Went there to get ur clothes n f--- me wow wat a commotion that was ay," part of her message read.

Eade also phoned her partner, who was in Canberra's jail, later that day and spoke of how she and Engeler had "bashed Sam".

On Friday, the court heard Bailey Hagen had spent 216 days in pre-sentence custody but only 96 days of that time was solely referable to this incident.

MORE COURT AND CRIME NEWS:

Prosecutor Beth Morrisroe said his eventual sentence should therefore be backdated to start in June, arguing the young man should receive a "reasonably significant" jail term with supervision in place upon his release.

Defence barrister Stephen Robinson, instructed by solicitor Anastasia Qvist, asked Justice Geoffrey Kennett to start the sentence earlier, in April.

Mr Robinson argued that if Bailey Hagen was not released from custody immediately, that should happen "in a month or two".

He said his client should be afforded more leniency than a more "normal" person who had committed the same crimes, taking into account the man's disadvantaged childhood, lower than average IQ and "mental condition".

Mr Robinson added that Bailey Hagen had taken "a big leap" towards reform last time he was in the community, and there was still "a strong degree of hope" for his rehabilitation.

Justice Kennett indicated he would aim to sentence Bailey Hagen next week.

The court heard Trinity Hagen had pleaded guilty to the same charges and would be sentenced in December, while Engeler and Eade had already been dealt with.

Ms Morrisroe said the prosecution of the child involved in the incident had been discontinued.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: