I think the best punishment before execution would also be a slap in the face to the MSM. For the court to declare that he is “not a Muslim, because Muslims do not commit such evil acts”, so that while awaiting execution, he should be “denied such religious privileges that are given to those of religious faith”.
That means: no beard, no skullcap, no prayer rug, no permission to attend prayer services with Muslims, no religious counseling, and then after execution, that his remains be denied Muslim ritual funerary services, but are interred with the remains of non-religious prisoners.
Death of 1000 cuts with salted pig fat over a period of 5 days!