Capos were selected from prisoners who tried to gain the favour of camp guards by collaborating, informing and taking part in sadistic acts against other inmates. In return, they would have power over regular prisoners (essentially becoming foremen), higher quality rations and a degree of respite from the beatings and random killings doled out by the guards.
During the expansion of the many Auschwitz satellite camps, capos were in short supply, as it was estimated that every twenty prisoners would require a capo. To remedy this, capos were selected from the criminal population present at many concentration camps, and relocated to Auschwitz. According to Joseph Borkin’s Crime and Punishment of IG Farben, criminals were regarded to possess the “special talents” required to make effective capos.
Capos were created to turn prisoners against one another (instead of against the guards), to give camp officials information on prisoner activity (escape plans, uprisings etc.) and to delegate guard duties down to the inmates themselves. In respect to the latter point, capos were responsible for a certain number of prisoners, and would be in charge of keeping track of inmates during the daily roll calls.
Capos would also be responsible for maintaining discipline and quality of labour amongst the prisoners in their charge, and could be punished if camp administrators felt that it had fallen too low. Quite often, capos would pass any punishments they had received down to their subalterns.
In terms of daily life, they would generally live amongst the section of the camp population that they oversaw, but would have a higher degree of choice than the average prisoner. They would be able to choose the warmest bunk to sleep in, skip food lines, be exempt from most hard labour, and avoid most beatings from guards.
In many cases, capos were considered by prisoners to be just as brutal as SS guards (if not worse), but were far more unpredictable in their assaults on inmates. Capos were desperate to maintain their position in such a hostile environment, and would be willing to do anything to ensure their favour remained with the guards.
Very few capos survived after liberation. Like the sonderkommando, they were generally killed by the SS due to their high degree of involvement. If not killed by the guards, they would be killed by their fellow inmates for retribution or shot by Allied liberators alongside SS guards.
Sources:
Hermann Langbein – People in Auschwitz
Duncan Little – Allies in Auschwitz
Joseph Borkin – Crime and Punishment of IG Farben