I don't believe in the after-life, and I do believe there are some malformations of the neural chemistry that lead to behaviors so heinous that no amount of therapy can ever make that person normal again.  

Evil persons can change. However, whether they change or not, if they take a life, government authorities may decide to execute them, as a consequence of their actions. (Romans 13:1-4)

Do you think it is right to forever lock up people who are evil and never going to change?

I say execution is preferable to life in prison. For society, and for the criminal.

You would think those who do not believe in the after life would take extra care to not screw up this one.  But they do and I agree with you except there is an afterlife.

I think that some people need to be locked up forever.  I think some people need to be croaked too.

They can.  SOME can.  Some are constitutionally incapable for genetic or physical reasons we cannot fathom.

Well that is partly true.  I think it is preferable.  But for some who need to have the full monty, I think they should rot in hell in prison and forever. 

Thank God I don't make the rules.