Ask Google to remove email ALIAS (from a domain I own) from a GMAIL account

Facts:

1. I have a Google Apps account with my domain: example.com
2. I created a user for my domain: alice@example.com
3. Alice registers alice@example.com as an email alias for her gmail account: alice@gmail.com
4. Three years later, Alice leaves example.com
5. I delete her alice@example.com account from the Google Apps account. As expected, she can no longer get emails addressed to alice@example.com.
6. However, she can still send emails from alice@example.com using her gmail account since she keeps the email alias on it.

Question: is there a procedure to ask Google to remove that email alias from her account since I own the example.com domain?

Thanks!