The Church teaches that recourse to the death penalty is allowable if it is the only option left to defend a community against an aggressor(like a serial killer who has killed an enormous amount of people and shows no regret and will continue to kill if he had the chance). I think the death penalty of people like Ted Bundy was definitely justifiable.
Some popes and bishops are more for the death penalty than others. It is one of the things that the Church leaves open to debate regarding it. For instance Pope Pius XII, Pope Leo XIII or Bishop Fulton Sheen would seem more for the death penalty than John Paul II. The the bible itself practically commends it as a form of justice(Leviticus 24:16). At the word of our first pope, Peter, two people were put to death. There are other supporting positions for capital punishment in the New Testament:
Acts 5:5-10 - When Ananias heard these words he fell down and breathed his last and great fear came upon all who heard of it. The young men came and wrapped him up then carried him out and buried him. After an interval of about three hours his wife (Sapphira) came in unaware of what had happened. Peter said to her "Tell me, did you sell the land for this amount?" She answered "Yes, for that amount." Then Peter said to her "Why did you agree to test the Spirit of the Lord? Listen, the footsteps of those who have buried your husband are at the door, and they will carry you out." At once she fell down at his feet and breathed her last. (Note: Both Ananias and Sapphira had quick easy deaths but will suffer with the damned for eternity.)
That's why the Church leaves it up to the state to decide on regarding the death penalty considering so many different factors arise in each and every case, and no case is the same. Thats why now Pope cardinal Jospeh Razinger stated:
"For example, if a Catholic were to be at odds with the Holy Father on the application of capital punishment or on the decision to wage war, he would not for that reason be considered unworthy to present himself to receive Holy Communion. While the Church exhorts civil authorities to seek peace, not war, and to exercise discretion and mercy in imposing punishment on criminals, it may still be permissible to take up arms to repel an aggressor or to have recourse to capital punishment. There may be a legitimate diversity of opinion even among Catholics about waging war and applying the death penalty, but not however with regard to abortion and euthanasia." - Worthiness to receive holy communion
Clement, the Bishop of Rome from 90-100 C.E., argued that God alone rules all things, that He lays down the law, punishing rebels and rewarding the obedient, and that His authority is delegated to Church leaders. Clement went as far as to say that whoever disobeys these divinely ordained authorities has disobeyed God Himself and should receive the death penalty.
Even in the beginning of the twentieth century, Pope Leo XIII argued that the ends justified the means. He said :
[FONT=Times New Roman,Times]
[/FONT]The death sentence is a necessary and efficacious means for the Church to attain its end, when rebels act against it. - Pope Leo XIII
If I have committed a crime or done anything deserving death, I do not seek to escape the death penalty; but if there is no substance to the charges they are bringing against me, then no one has the right to hand me over to them. I appeal to Caesar." [Acts 25:11] Saint Paul's clear acknowledgment of deserved death sentences and that he would not seek to escape a justified sentence of death.
Although they know the just decree of God that all who practice such things deserve death, they not only do them but give approval to those who practice them. [Rom. 1:32] Statement of Saint Paul that the death penalty is a just decree of God for various offenses.
The Church's teaching has not changed, nor has the Pope said that it has. The Catechism and the Pope state that the state has the right to exact the death penalty. Nations have the right to just war and individuals have the right to self-defense.
Now of course it would be a great world if society did not need the death penalty. And this is what we pray for when we hope to end it.