If you think you have a computer security problem and the operating system has been pwned, you don't hire some random person off Fiverr to "scan" your computer.
That's the most implausible thing about this - the university is suggesting that a vet is some kind of l337 hacker. In my experience vets and hackers are about the most distant groups of people possible.
However, it is plausible that someone else stole the librarian's password, created the account and sold access to her.