You can't really delete evidence like that, it's backed up in ways normal agents or operatives can't touch. The FBI has servers that back up in ways that agents and anyone else can't even access. If it was ever emailed, put in a memo, or shared in any way there is a backup.

Pam Bondi said she had the reports and THOUSANDS of hours of video footage of many different people abusing children. However she got it, and whoever sent it to her unknowingly created a backup in the system.