Police are now calling for new witnesses to help push forward an investigation that has so far failed to lead to any charges, six months after the attack.

A prison camera was repositioned before a number of assailants entered the cell of Steven Freeman, 24, on April 28.

He was bashed severely, and was only kept alive by the efforts of prison officers, who performed first aid and resuscitated the inmate.

Paramedics rushed the prisoner to hospital, and he was placed in an induced coma for almost a week. There were fears of lasting brain damage at the time of the attack, and Freeman required multiple operations.

Freeman's lawyers, the Aboriginal Legal Service, described the repositioning of the camera as a "remarkable coincidence", and members of the ACT's Indigenous community have called for an independent inquiry.

The young man, aged in his 20s, had only been in prison a matter of hours.

Investigations have been complicated by Freeman's claimed inability to have any recollection of the attack.

But ACT Policing revealed on Tuesday that they had conducted forensic analysis on fingerless gloves and a bloodied shoe found at the Alexander Maconochie Centre the next day.

That analysis, they said, had identified three persons of interest.

"ACT Policing believes there may be members of the community who have information about the assault on 28 April 2015," police said in a statement.

Freeman was in custody over a series of offences, and was suspected of involvement in a crash that left a teenage girl, who was his front seat passenger, with a broken back.

He remains in custody at the Alexander Maconochie Centre, where prison authorities have taken numerous steps to keep him safe.

Anyone with information should contact Crime Stoppers on 1800 333 000 or via act.crimestoppers.com.au.