From Halopedia, the Halo wiki
A convict, also called a prisoner, is an individual imprisoned and deprived of personal freedoms after being found guilty of a crime by some form of authority. Individuals can be imprisoned for various reasons ranging from minor violations like theft to major crimes such as murder, piracy, terrorism, and treason. Convicts are incarcerated by their own peers unlike prisoners of war, who are combatants imprisoned by enemies forces following an armed conflict. While in captivity, prisoners are typically fitted with physical restraints. Both human and Covenant often send their convicted criminals on prison ships to distant labor and correctional facilities, known as penal colonies. Aboard military bases, vessels or space stations, prisoners are detained in a holding jail called a Brig.
During the Human-Covenant War, UNSC humans could be punished with life imprisonment or execution if they violated the Cole Protocol. Human convicts would have prison barcodes tattooed onto their arms and would also be implanted with a tracking chip.
The Covenant Empire was known to incarcerate convicted client species in High Charity and in other detention facilities, where they were often tortured and disposed of. In some cases, Sangheili or Jiralhanae guards disposed of criminals by feeding them to Kig-Yar convicts, who would eat their victims alive.
Covenant cells and prisons are seemingly segregated by race. One such penitentiary, called Weeping Shadows of Sorrow, detained only Sangheili convicts. It was at this very facility where Ripa 'Moramee was incarcerated after being found guilty of staging a coup against his clan's Kaidon. 'Moramee's sentence was annulled when he was appointed Arbiter by the Prophet of Regret.
Although not seemingly convicted of any crimes, the Unmutuals, asocial Yanmee'e who suffered from personality disorders, were sentenced to work to death in penal colonies operated by Mgalekgolo and Kig-Yar guards.
In addition, disgraced warriors found by the High Council to be guilty of heresy would be publicly tortured and branded with the Mark of Shame, only to be sentenced to death soon after. This fate awaited Supreme Commander Thel 'Vadamee following his defeat at Installation 04. The terms of his execution were left in the hands of the Hierarchs, who overruled the council and allowed 'Vadamee to redeem himself by becoming the next Arbiter.
As an act of penance, Forerunners who had committed crimes could volunteer to be reformed and serve the Juridical rate as evidence-gathering agents. Those who did had their biological bodies reduced to a shriveled form and encased in a mechanical carapace. They were stripped of their individuality and personhood, becoming a collective entity committed to investigating criminal actions by citizens of the Ecumene. Security spires, large suspended detention centers, were utilized by Forerunner to contain or isolate dangerous beings.
List of notable prisoners
List of appearances