Is it permissible to eat food from someone who works in a riba (usury or interest) bank?

Question:
What is the ruling on eating at the home of a person who works in a riba bank, given that he is a close relative?

Answer:
If he has income from other lawful sources, then it is permissible to eat his food. If he has some haram (forbidden) or doubtful income, but he also has other money that is pure and permissible, then it is permissible to eat his food, because it is not established that this food comes from forbidden earnings. As for the person whose entire earnings are haram and who has no lawful income, then it is not permissible to eat his food.