Are the profits from a new deposit in an Islamic bank permissible, knowing that the principal amount originated from previous usurious interest?

1. It is forbidden to deposit money in usurious savings or investment accounts. Anyone afflicted by this should transfer their money to a non-usurious account.

2. If money is withdrawn and it is found to be from usurious interest, there is no harm in investing it and considering it part of the principal, while disposing of the interest when the restriction is lifted and the remaining money is withdrawn.

3. Due diligence must be exercised regarding Islamic banks in the inquirer's country, as it has been found that they deposit a portion of the money in usurious treasury bills. Even if they are compelled to do so, the customer is not compelled, and it is forbidden for him to make investment deposits with them. He should suffice with placing his money in a current account.