What is Your Eminence's opinion on praying behind an Imam who built a house with a usurious loan?

Dealing with usury is one of the greatest abominations, and the Imam who deals with usury must repent to Allah. If he repents, then prayer behind him is valid. However, if he does not repent, he is a transgressor, and prayer behind him is valid according to the majority of scholars, even though the Imams disliked praying behind transgressors, and praying behind righteous individuals is more befitting.