Too soon to say, but if it was an explosion and it was from inside out, then yes internal saboteur.
But I think IAEA may have a hand in this....
remember this?
The inspector then "sneaked off" to the toilet while she was waiting for a further security check, he said.
"There was no doubt that suspicious material was involved."
The inspector was prevented from entering a facility over concerns she had "suspicious material".
www.bbc.com
Mossad has likely been using IAEA agents to smuggle in bomb making material into Iran for years. Then an internal saboteur can take the material from what location it was safely hidden in (already snuck inside) and place it for future detonation on target for when Iran passes certain Mossad red lines.
This removes the risk of the internal saboteur (scientist, engineer, etc) from getting caught trying to smuggle something in that would likely get him executed.
Iran’s large scale enrichment program is possibly destroyed. Those centrifuges may no longer be able to be used if the enriched uranium is “stuck” inside them for long period of time or depending on how violent the shut down was if the motors sustained damage.
And with no major workshop (thanks to previous sabotage) Iran has a token amount of centrifuges at Fordow that make break out enrichment time basically a snails pace.
Simply inexcusable. If Salehi still has his job after this, all remaining respect for Iran’s civilian nuclear program will go down the drain