What is the punishment when innocent people are incorrectly executed under Sharia, and who is punished?

For certain actions, e.g. murder, Sharia may prescribe the death penalty , which is implemented in some Muslim-majority countries. This opens the possibility that an innocent person could be mistakenly executed. This situation could be regarded as murder, and hence might attract the death penalty too. **Question**: What is the punishment when innocent people are incorrectly executed under Sharia, and who is punished? It seems possible that there is no punishment, since the hypothetical incorrect execution was a mistake. However, that feels unjust.