A Capo (or Kapo) was a prisoner trusted by the SS and given various duties and privileges. At many camps Capos were in charge of the distribution of food in a block (at the the camp) and had the right to whip prisoners for minor breaches of discipline.
One of the more revolting features of the Holocaust was that the victims, viewed collectively, were forced to collaborate with their own destruction.
A few Capos seem to have collaborated quite happily(!), and some were tried and convicted of various crimes after the war. A few were hanged.
A concentration camp prisoner who took charge of other prisoners for the Nazis in order to gain personal power or advantage from his or her captors.
Kapos were the inmate trustees who carried out the instructions
camp commandants and concentration camp guards.