Won't know until in a few decades it all gets declassified but my bet was always a US Navy Special Warfare team, aka SEAL team. That is who the US uses for such operations. Previous week there had been US Navy units doing exercises in the general area. The level of hostility, type of aggressive narrative control, and how key US outlets were already standing ready to suppress certain details made it suspicious from the start.

The US uses the same playbook again and again, makes people suspicious even when the US might not have been involved in events.