The old bonds that we once bought at the bank, no longer exist. Most are electronic entries now. A number of years ago I converted a bunch of paper bonds to electronic entries. As they reach final maturity we move the proceeds to our bank account.
It is not a user friendly process, but I’m sure they have an electronic paper trail.
Bonds take a year to mature, so this was a long game. It would make more sense to buy paper “gift” bonds and have them mailed to a drop box. Holding them for a year electronically is simply too high risk.
Identity theft to buy savings bonds has to be somebody very familiar with the treasury bond system i.e., a current or former federal employee with the treasury department.