If in January, Putin was making promises that the Nord would be removed while Biden was stating the Nord must be left intact, there would be some legitimate reasons to blame Russia for the sabotage.
The fact that the DS and the media are speaking in one voice without any actual facts to present makes me think that the US might have done it. But in reality, us ‘little folks’ have no idea whodunnit. Could have been Hizbollah, Taliban, ISIS (___fill in the blanks).