We know we (the US) had some prisoners. The question is did we have them before the raid or after the raid? It would look pretty bad for the Obama administration to have prisoners in Libya. If we captured people during the raid, why would we turn them over to anyone? Was this a raid to grab the Ambassador and trade him for some prisoners in Benghazi? Whoops.
How would it look if the Obama administration had prisoners in Libya after the Democrats screamed about Bush doing this and Obama signs a law saying we won’t do it? And then some thugs kidnap our Ambassador to trade him for these Libyan prisoners. We agree, and give them the prisoners and they give us a dead Ambassador. Ouch. That doesn’t look good for the Obama administration either.