This is the second time in as many days I've seen some one use the argument that the severity of the crime meant the standards for conviction should somehow be less stringent. Sadly, I don't get the impression is an uncommon way of thinking.
This line of thinking peeks through all the time from otherwise intelligent people. Merely mentioning how heinous a crime was when we're talking about the guilt or innocence of a suspect should immediately kill your credibility. Too bad the criminal justice system doesn't care about that.
Horribly, you regularly see this in supreme court cases. Some case has the conservatives denying a significant right to a criminal suspect and the decision will start with a lurid depiction of the crime they were convicted of through the denial of some right.
its not a deterrent for multiple other reasons too:
1. most murderers do not expect to get caught if they are acting at all rationally, and do not care if they do not, and,
2. unless you execute a high proportion of people committing a particular crime any one criminal knows they are unlikely to be executed.
I think the Tutu quote at the end of the video.
Most of the rest of the work world has abolished capital punishment, and most of the rest uses it very sparingly. The big exceptions are China and the Middle East. Good company to keep?