Not likely to be of more than one nationality. Too close-held for that. And it required technical divers (not SEALs) with a recompression chamber available. The idea it was done by six non-state SCUBA divers on a chartered yacht is a really lame backup cover story. Might as well say I climbed Mt. Everest barefoot with no oxygen tanks.
I read there was a navy vessel not terribly far from the area that day. Of course they denied that it had anything to with this incident.