the unknown sis 

یَـٰۤأَیُّهَا ٱلَّذِینَ ءَامَنُوۤا۟ إِن جَاۤءَكُمۡ فَاسِقُۢ بِنَبَإࣲ فَتَبَیَّنُوۤا۟ أَن تُصِیبُوا۟ قَوۡمَۢا بِجَهَـٰلَةࣲ فَتُصۡبِحُوا۟ عَلَىٰ مَا فَعَلۡتُمۡ نَـٰدِمِینَ ﴿ ٦ ﴾ 


O you who have believed, if there comes to you a disobedient one with information, investigate, lest you harm a people out of ignorance and become, over what you have done, regretful. (6)

Al-Hujurat, Ayah 6