Does the Zakat obligation fall away from the owner of the wealth if it is stolen from the poor person who was entrusted with distributing it before he was able to do so?

The portion that the poor person received for himself alone is deducted from the Zakat, because he took possession of it, and it reached its rightful recipient. As for anything in excess of that, it is not deducted because it did not reach its rightful recipients. The poor person (the agent) is not obligated to guarantee the money taken from him by force, unless he was negligent in its preservation or delivery. This is because the agent is trustworthy and is only liable in cases of negligence or transgression. So, if the Zakat was stolen before its distribution, its owner must pay a replacement for it because the agent is his agent, not an agent for the poor. If the agent transgresses or is negligent, he is liable; otherwise, he is not. The opinion that it is obligatory to pay (a replacement) is more cautious and clears one's conscience.