What is the ruling of Islamic law concerning a man who built shops on land designated for a mosque, then claimed ownership of them under the pretense of contributing to the mosque's renovation, while everyone knows that both the land and the shops are an endowment for the mosque?

If a person usurps land endowed for a mosque and the shops built upon it, and annexes it to his own land, this is unlawful (haram) and a grave sin, because usurping an endowment (waqf) is more reprehensible than usurping other property. This person must sincerely repent and return what he usurped to the mosque, along with any benefits he gained from it, and guarantee any damage or deficiency, because benefits are like wealth. The jurists mentioned that the supervisor of an endowment is not permitted to sell or rent the endowment to himself or his relatives, out of fear of favoritism.