Am I sinful if I employ someone in a telecommunications company, and then it becomes clear to me that his papers have been transferred to a usurious bank and he has been accepted there, and is it permissible for me to take my agreed-upon percentage of the profit after the recruitment company receives its invoice from the bank?

It is clear that the aforementioned contract is a permissable 'جعالة' (reward-based contract) according to Islamic law, based on the verse: "And for he who brings it is the burden of a camel, and I am responsible for it." The condition is that the 'جعالة' (reward) must be known. If the commission is a known percentage of the salary, then it is permissible. However, if the salary is unknown at the time of the contract, then it is a void 'جعالة' according to the majority of scholars, and the one who performs the task is entitled to a fair wage (اجرة المثل). Some scholars have opined that ignorance of the compensation is permissible if it does not prevent delivery, such as when the reward is a percentage of the salary that will become known later. As for the company transferring the employee to an interest-based bank, there is no sin on the questioner for this, and it does not prevent him from benefiting from the deserved 'جعالة'.