His incarceration may have saved someone's life, and quite possibly protected him from an early death on the streets. He did have a gun afterall. The criminal justice system is just one of many systems that are screwed up. The irony (to me) is that too few beyond-a-doubt murderers are executed. Child molestation, kidnapping, as well as party-to-a murder offenders should also (actually) be executed.
Two issues. First off, kidnapping and child molestations mean a variety of things. It can be something as simple as a father picking up his child when the mother has custody because he knows the mother isn't taking good care of him (but is having a hard time proving it at court). To suggest that deserves the death penalty is quite draconian, I might as well suggest your use of the word after all, namely forgetting to put the space, deserves the death penalty. The same issue is with child molestation. One case next door to where the parents of my boss live involves a 19 year old who may be charged for molesting a 16 year old child, when the child was well known for sleeping around with those 17/18 years old (which was legal due to the 2 year age gap). You are suggesting we execute people for engaging in consensual sex just because conservative laws have yet to be overturned on the issue? We might as well go back to executing people for adultery or homosexuality.
Now, perhaps you mean
real kidnapping/child rape cases like those you see on the news, but you aren't going to be able to pass a law that only targets them. Thus, in interest of not having protective fathers and teenager boyfriends all over the US being executed, I will have to disagree with you until we change the law such that they aren't the same crime.
Also, giving them the death penalty may end up with more children being murdered and traumatized, for reasons ranging from the simple "don't want to get caught" to far more complex issues. A child suffers when they are molested by a parent, but they will often times suffer more when they lose the parent, often times blaming his/herself for losing the parent. Add on the blame for being responsible for the death of the parent, and you are sure to end up with psychotic mad-adapted individual. Now, we can agree the child isn't at fault, but that doesn't stop the child from blaming him/herself, and it doesn't stop friends/family of the accused from blaming the child either.
But the issue here isn't that the punishment was wrong for the crime, it was that the prosecutor covered up evidence that would have found him innocent. The prosecutor should be prosecuted for kidnapping and holding someone against their will for nearly two decades and conspiracy to commit murder.