Making Salaam after the Third Rakaah in a Four Rakaah Salaah

Q: Salaah-407: Our Imaam made the Salaam after the third Rakaahs of a four Rakaah salaah. When the Muqtadis told him about it, he said, the salaah will be valid if we perform another Rakaah". He then performed another Rakaah, performed Sajdah Sahw and then made Salaam. Is the salaah valid? Furthermore, another person joined the Jamaa'ah in this four- Rakaah. Will his salaah be valid?

Answer: Because the Imaam spoke after the third Rakaah, the three Rakaahs were nullified and will not be redeemed even though he added a Rakaah and performed Sajdah Sahw. All four Rakaahs need to be repeated The salaah of the latecomer will also be invalid. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2