“Using receipts”
If they had a damning “receipt” they would shown it.
The “four hairs” story is maybe the most embarassing thing about the FBI’s report. Why did they put it in? Did their scare-mongering specialist wordsmith slip up? The wordsmith is talented otherwise, creator of the ominous “sole custodian” phrase.
Yes, use of the phrase “sole custodian” is outrageous unless they go on to say that 8 samples were identical and 100 people were KNOWN to have access. (And of course an unknown additional number of people).