I know there is a lot of static about the change that Pope Francis appears to have made to the Catechism (I am not speaking about the legitimacy of what he did, nor about what he means or intends by it). The Catholic Church has always taught that capital punishment is a good and necessary practice and that to reject it was an injustice to society. It certainly appears like the Pope wishes to change that position of the Church, and there are some Canon Lawyers who are saying he cannot do that. I encourage you get the definitive book on the subject (link below) and learn what the Church has always taught. Once you do that, you can understand better what is going on today and be able to be more discerning.
"By Man Shall His Blood Be Shed--A Catholic Defense of Capital Punishment" by Edward Feser and Joseph M. Bessette.