But not everyone believes killing a killer -- is justice served.
"No reasonable person can look at the system we have now and say it's fair and accurate," says David Kaczynski, brother of "Unabomer" Ted Kaczynski.
He fought and saved his brother from the death penalty, and since then has dedicated his life to abolishing what he believes is a flawed and ineffective system.
It is his hope that helping to get the death penalty scrapped would rewrite his family's legacy.
On CBS News Sunday Morning, correspondent Erin Moriarty of 48 Hours talks with David Kaczynski and others, in a fresh look at the continuing controversy over the death penalty.
At a recent hearing to determine whether New York should outlaw the death penalty, there was a familiar face among those speaking out against it.
Moriarty says David Kaczynski is what you might call an accidental activist: proof that you don't always get to choose your path in life. Sometimes life -- chooses for you.
"I was one of those people," David Kaczynski told Moriarty, "that said using violence and killing to address, you know, violence and killing, sends the wrong message. But it was only a hypothetical thing for me. …When the death penalty came knocking at my door, it was something else.
For 17 years in the 1980s and 1990s, Ted Kaczynski terrorized the country, sending bombs packed with nails and razors through the mail. Three people were killed, and 23 were injured and maimed. In 1996, federal authorities finally arrested Ted Kaczynski, but only after David turned him in.
In 1995, federal agents were trying desperately to identify and track down the man known only as "The Unabomber." In upstate New York, David Kaczynski and his wife had an uneasy feeling that they knew the killer's name.
Whose idea was it originally, Moriarity wanted to know. "It was my wife, Linda's," David Kaczynski answered. "She had actually sat down one day and said, 'David, did you ever consider the possibility that your brother Ted might be the Unabomber?' And you could have knocked me over with a feather. …Admittedly, he's strange; admittedly, we think he's mentally ill. But a killer? I can't imagine that."
It became easier to imagine when, that summer, The Washington Post published the killer's "manifesto," passages that seemed to match what David's brother had written in the past.
"If I did nothing," David tells Moriarty, "there was a good chance Ted was the Unabomber, and some other person would be blown up or maimed. On the other hand, I think that everybody thought the Unabomber would be a candidate for execution. The likelihood would be that I'd either have some innocent person's blood on my hands if I did nothing, or my brother's blood on my hands if I stepped forward."
But he did contact the FBI, and on April 3, 1996, Ted Kaczynski was arrested. In his Montana cabin was a live bomb ready to be mailed to another victim.
"It was, 'Thank God,' you know, 'Thank god we came forward.' "
But if David felt relief, he also felt a great deal of guilt.
"Clearly, he had to be stopped. I don't think there was any other way to stop him. On the other hand, I sometimes think, you, know -- earlier in his life, he was my older brother. …Maybe if I had recognized how seriously disturbed he was, I could have been more helpful to him.
"You haven't been able to talk to him?" Moriarty asked. "Mom and I have written to him often."
But he hasn't responded?
"Never. Never has."
What made things worse, says David, is that federal prosecutors betrayed him: He says, after promising to get his brother psychiatric help, they asked for the death sentence instead.
It was while fighting to save his brother's life that David's own life changed. He has been on a mission to end capital punishment ever since.
David was able to get his brother life in prison with the help of high-powered lawyers – proof, he says, of how arbitrary the system can be.
But the strongest evidence against the death penalty, says David, is Juan Melendez-Colon. He spent nearly 18 years on Florida's death row for murder -- before a taped confession by the real killer was discovered, and Melendez-Colon was released.
"Aren't you angry?" Moriarty asked him. "You lost 18 years of your life!"
"My anger," Melendez-Colon responded, "is a different type of anger. The anger that I have is the type that drives me to do what I'm doing. It's anger without hate. …It's a type of anger that drives me to let people know that this is wrong, without being bitter."
Since 1973, 117 inmates on death row have been set free. Melendez-Colon now travels the country making sure their story -- his story -- gets told.
"I was not saved by the system. I was saved despite the system. I was saved by the grace of god."
"I would say," David Kaczynski asserts, "that reasonable people can disagree about the ultimate morality of executions. (But) no reasonable person can look at the system we have now and claim that it's fair and accurate."
He's got a point, Moriarty says: Five years ago, then-Illinois Gov. George Ryan, outraged that 13 inmates on his state's death row had recently been found not guilty and set free, commuted the death sentences of all 167 of Illinois' inmates who had been scheduled to die. "I now favor a moratorium," he said, "because I have grave concerns about our state's shameful record for convicting innocent people and putting them on death row."
Since then, several states, such as New York, have considered rewriting their death penalty statutes or eliminating them altogether.
But, Moriarty points out, the question then becomes -- what to do with killers like Michael Ross?
In the early '80s, Moriarty reports, Ross went on a killing spree in New York and Connecticut, strangling eight women. Most were raped.
There's no question of his guilt -- he confessed and led police to the bodies. Still, David Kaczynski questions the benefit of executing anyone.
"I don't think the death penalty accomplishes anything. In other words, killing the person who committed some horrendous crime, in my view, has no social benefit to it."
Try telling that to Edwin Shelley.
"My daughter's up in Patchogue Cmetery four foot down, never to see the light of day again. Never to have children. I mean, 21 years. She was 14. She'd be 35 today."
Shelly's daughter Leslie was kidnapped by Ross along with her best friend, April Brunais.
"Her friend," Shelley says, "was raped and murdered. And Leslie was tied up in the car, knowing what was happening to her friend.
"When he came back and took her out, he put her on her stomach and said, "I'm sorry," and killed her. And this man doesn't deserve to die?" Shelley cried.
How does executing Michael Ross help you and other victims? "It renews our faith in the judicial system," Shelley says. "I want to see him dead. You can say revenge. Yes. Yes. There has to be revenge involved in it. But also, as the Bible says, a life for a life."
You are not only for the death penalty, you want to be there when Michael Ross is executed? Moriarty asked.
"Oh, yes," Shelley replied. "I want him to know that the way he looked at my daughter as he murdered her, I will be watching him when he dies."
Last Wednesday, Shelly thought he would finally get his wish, 21 years after Leslie's murder. Ross was scheduled to die by lethal injection. But a last minute stay was granted even though, ironically, Ross himself says he wants to die.
"I owe these people," Ross says. "I owe them. I killed their daughters and, you know -- if I could stop the pain—I had to do that. What I'm hoping is that January 26th, I will be executed, and that will be the day they can start letting go of the anger."
The fact is, it's getting harder every year to carry out an execution, Moriarty notes. Since being reinstated by the Supreme Court in 1976, executions reached a peak with 98 in 1999. But since the problems on the Illinois death row were uncovered, the number has dropped sharply, to just 59 in 2004.
But David Kaczynski believes -- that's still 59 too many.
David now runs New Yorkers Against the Death Penalty.
The $1 million dollar reward he collected for turning in his brother went into a fund to help Unabomber victims.
"What keeps you going," Moriarty inquired. "What keeps you in this?"
"It's a good question," David answered. "I think it's a passion for justice. It's a passion for human value. It's a passion for human dignity."
He is hoping the Kaczynski name, which will forever be associated with so much evil, might someday be remembered for something else.
"I think that most of us who have been affected by tragedies involving violence look for some kind of saving grace. Like, we really, really do want, as unlikely as it may seem, something good to emerge -- from something terrible."