I support the death penalty so that people will be affraid to commit crime, but be sure that the person who commited the crime is the one who is being punished. Not the one who is accused and suffer the consequence.
And here's the problem. You can never be 100% sure that the person being executed was also the one committing the crime. There are a lot of cases where people where found innocent just in time - or to late. How much a margin of error - ie. innocent lifes lost - is it worth to keep the death sentence?