Yehuda ben Tabbai's feelings of guilt knew no bounds. "All his days, Yehuda ben Tabbai prostrated himself on the grave of the executed man, and his voice used to be heard. The people believed that it was the voice of the executed man; [but] he said to them: 'It is my voice. You shall know this [by the fact that] on the morrow [when] I die, my voice will not be heard'". Yehuda ben Tabbai had, through a terrible mistake, killed an innocent man, and he carried that burden with him to the day he died.
 Does this rule have an exception? Rav Soloveitchik in The Lord is Righteous in All His Ways, p. 274, wonders without resolution, whether leaders of the Nazi movement, yemach shemam, could have their teshuva accepted.
 Those who require semicha, the laying of hands, would not invalidate a sacrifice if such was not done, and those who forbidsemicha admit that no Biblical law is violated if such is done.