Musalla on a land whose owner is unknown

Q: In the Masjid (mosque) of Prince Salman ibn Muhammad Al Su`ud, we suffer from the narrowness of the place, which does not accommodate the number of those who offer Salah (Prayer) and does not include a place for women to offer Salah therein. During Ramadan, we pitch a large tent for women on a piece of land behind the Masjid, but it is exposed to cats, children, and even rain, (Part No. 5; Page No. 192

A: The basic rule states that it is not permissible to use others' properties in any way, whether by constructing buildings on them or by using them for any activity, without the permission of their owner. Therefore, you should search for an alternative other than this land. Moreover, it is not permissible to build a Musalla outside a Masjid and make those offering Salah unable to see their Imam (the one who leads congregational Prayer). Likewise, it is not permissible for the one who offers Salah in this place to be led by that Imam.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.