By having the private keys, law enforcement was able to seize all the Bitcoin controlled by those keys.
If ChipMixer would have deleted them after handing out a chip, they wouldn't have been able to do that.
We do not know what it the content and source of 7GB data mentioned before. I may imagine the situation where CM operator
deleted private keys and/or session data as it was promised, but if server has been hosted using serious datacenter, regular backups were done. In my opinion it is not impossible that some data comes from backups (restore points) made by hosting operator.
It is 7TB. If backups were done that include the private keys, that was a big mistake. I can guarantee you that these 7TB include private keys, since I have seen funds withdrawn from ChipMixer (imported private keys)) disappear on the day of the ChipMixer takedown.
It is still hard for me to believe that Chipmixer, which we have considered reliable and supported by the most honest members of the forum for years, has kept user data in those 7 terabytes that were discovered.
It occurred to me that it might contain nodes data that Chipmixer was supposed to be running on the blockchain. I don't expect that ChipMixer uses nodes from another party.
In addition, of course, to the private keys for the chips that were being produced for the service. Is it possible that the size of these nodes is 7 terabytes?