This article addresses the issue of criminal prosecution of crimes within prisons in light of the principle of equality before the law and nondiscrimination. We ask whether the institutional answer to crimes where the victim is a person deprived of liberty reaches the same standard as that for crimes that occur outside prison. To this end, we compare the results of criminal investigations carried out by the Chilean Public Prosecutor’s Office over a 12-year period with respect to homicides, injuries and sexual violence, both inside and outside of prison. The conclusions indicate that there is an inequality in the institutional response to crimes committed inside prison, and that this difference implies a factual discrimination against victims deprived of liberty, which makes them second-class victims.