They can appeal. And as far as I know one of them doesn't want to appeal. Western media of course says about tortures in bloody KGB. Mother of one of them also wrote a petition to the President but it was dismissed.
We will never know why and whether they did it. But those who did it should be punished. I was happy that my sister that day was late from work. She usually went there that time.
Israel and Interpol persons confirmed investigation. So I can believe that "bombers" were involved in the crime.
People are executed by the pistol.