Is it permissible to allow a Hindu engineer build a mosque, knowing that there is very close supervision in the process of building?

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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

It is not permissible to allow a Hindu engineer or any non-Muslim to build a mosque as long as there are Muslim individuals who can do so. Non-Muslims are sworn enemies to this religion, its people and rituals and thus they cannot be trusted to not cheat in designing the plans of the mosques or implementing them. They may make their design similar to or resembling that of their places of worship. However, if there is no Muslim engineer or the building and work of the non-Muslim will be under the supervision of a Muslim in a way that the non-Muslim will not be able to cheat or change anything, then there will be no harm in this.

Allaah Knows best.