Assalamualaikum,
First of all, I would like to thank you for responding to questions quickly. Jazkallah khair. My question is regarding mutah marraiage. It is well known that it is prohibited from authentic narrations. But in Shias, it is allowed form of marriage. I dont have any doubt that it is haraam. But can we consider those shias who do it are commiting zina. If yes, do we also consider marriages between non-Muslims invalid and they are also commiting zina?
Wassalam

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Al-Mut’ah marriage is a void and forbidden marriage as clarified in Fataawa 84187 and 82221. However, according to the view of the majority of the scholars the ruling of Zina (fornication or adultery) does not apply to the one who marries a Mut’ah marriage; in which case, the children are traced back to the father and no Hadd (i.e. the corporal punishment determined by the Islamic Law) is applied on the one who marries such a marriage (a Mut’ah marriage).

As regards the marriages of the non-Muslims, the majority of the scholars are of the view that they are valid.