Well then fry the guy.
No, that might be hasty. Maybe the issue was clarified in the trial, and obfuscated in the article. The article itself is slanted. The guy got the death penalty for a murder, not the robbery in question.
The anti-death penalty advocates do sometimes rely on inaccurate data or illogical conclusions to make their case, but there is just not enough data to tell from the article.
There was a case from the 70’s or early 80’s that the anti-death penalty activists were trying to get thrown out in the 2000s because there “was no DNA evidence” found at the scene tying the accused to the scene. Well, back then, cops did not routinely collect such evidence, was a good reason why, on top of the illogic of the claim. They had three witnesses and a confession, but the new jury was swayed by the “lack of DNA evidence”.