We know good people disagree on the death penalty.
One important thing a Catholic needs to do is read what the church says about capital punishment in the Catechism in sections 2266, 2267 and 2268. The Church does not exclude recourse to the death penalty. It is easy for Catholics to become confused when some Catholics of authority take a contrary position to Church teaching on issues like the death penalty and say the Church opposes it.
A murderer violates the human dignity of the victim and the common good with his/her act of injustice. The race, social standing etc. of the murderer are not mitigating factors to the act of murder. Though, this is often suggested by some who oppose the death penalty. Some who oppose the death penalty also suggest supporters want vengeance. Read CCC 2268 below for the Church’s answer.
It is unlikely that a murderer will escape from a maximum security prison. However, murderers are in minimum and medium security prisons as well where escape is highly possible and interaction with others is daily. Human dignity certainly extends to people that are subject to constant interaction with the murderers; other prisoners, corrections workers, civilian workers and prison guards. It is important to know that few murderers are held in solitary confinement.
There must be justice for the victims of the murderer.
See CCC 2266, 2267 and 2268 below:
2266 The State’s effort to contain the spread of behaviors injurious to human rights and the fundamental rules of civil coexistence corresponds to the requirement of watching over the common good. Legitimate public authority has the right and duty to inflict penalties commensurate with the gravity of the crime. the primary scope of the penalty is to redress the disorder caused by the offense. When his punishment is voluntarily accepted by the offender, it takes on the value of expiation. Moreover, punishment, in addition to preserving public order and the safety of persons, has a medicinal scope: as far as possible it should contribute to the correction of the offender.
2267 The traditional teaching of the Church does not exclude, presupposing full ascertainment of the identity and responsibility of the offender, recourse to the death penalty, when this is the only practicable way to defend the lives of human beings effectively against the aggressor.”If, instead, bloodless means are sufficient to defend against the aggressor and to protect the safety of persons, public authority should limit itself to such means, because they better correspond to the concrete conditions of the common good and are more in conformity to the dignity of the human person.”Today, in fact, given the means at the State’s disposal to effectively repress crime by rendering inoffensive the one who has committed it, without depriving him definitively of the possibility of redeeming himself, cases of absolute necessity for suppression of the offender ‘today … are very rare, if not practically non- existent.'[John Paul II, Evangelium vitae 56.] Intentional homicide
2268 The fifth commandment forbids direct and intentional killing as gravely sinful. the murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance.