I don't think the video mentioned anything about an electron microscope. It's not emphasized, and not present at all in the audio, but there is "mention" withi

I don't think the video mentioned anything about an electron microscope. It's not emphasized, and not present at all in the audio, but there is "mention" within the video. At 8:40 in the video (https://youtu.be/9q3uNcJh4pc?t=516 https://youtu.be/9q3uNcJh4pc?t=516), when showing the response from Larsen, the sentence after the highlighting reads "a scanning electron microscope (SEM) examination ... would be necessary". So you are right that it wasn't done, but it apparently would have been the next step for a confirmation.