Working For Someone Who's Doing Illegal Activity & Giving Witness Against Owner
If one knows that a criminal activity is ongoing in a house then a Muslim should not work in that house and find a better alternative. And when asked to give witness then it is a requirement of our faith that we Muslims should always tell the truth, even if we have to give a witness against our parents and other relatives: يَا أَيُّهَا الَّذِينَ آمَنُواْ كُونُواْ قَوَّامِينَ بِالْقِسْطِ شُهَدَاء لِلّهِ وَلَوْ عَلَى أَنفُسِكُمْ أَوِ الْوَالِدَيْنِ وَالأَقْرَبِينَ إِن يَكُنْ غَنِيًّا أَوْ فَقَيرًا فَاللّهُ أَوْلَى بِهِمَا فَلاَ تَتَّبِعُواْ الْهَوَى أَن تَعْدِلُواْ وَإِن تَلْوُواْ أَوْ تُعْرِضُواْ فَإِنَّ اللّهَ كَانَ بِمَا تَعْمَلُونَ خَبِيرًا “ Believers, adhere to justice by bearing true witness before God, even though it be against yourselves, your parents, or your kinsfolk. If someone is rich or poor, God knows better about them both. So do not be led by base-desires, lest you swerve from the truth. If you distort your testimony or decline to give it, you should remember that God is well aware of all your deeds “. (Quran 4:135) The only exception would be in case of Iztirar where one had to give a false witness to protect his life or where one has to keep working there because of lack of another alternative and to not die of hunger.