Ruben Cantu was 17 in 1984 when he was charged with capital murder in the fatal shooting of a man during an attempted robbery in San Antonio. The victim was shot nine times with a rifle before the gunman unloaded more rounds into the only eyewitness.
The eyewitness, Juan Moreno, told the Chronicle that it wasn't Cantu who shot him. Moreno said he identified Cantu as the killer during his 1985 trial because he felt pressured and was afraid of authorities.
Cantu was executed at age 26. He had long professed his innocence.

If a person is put in jail for a long time, and years later if new evidence appears to prove him innocent the state can simply open the jail doors, perhaps pay the person some compensation money for being locked up for a part of his/her and let them go.

If a person is executed however, and years later if new evidence appears they are dead. There is nothing to be done to bring him/her back to life.

There are certain times when I do think the death penalty is just. If there is overwhelming DNA evidence, or if the crime is caught on camera, or maybe a credible confession...