has the account been hacked?
Personally I would have thought not.
My reason for saying that is if someone had hacked your partner's email account they would have discovered her password. If they knew her password they would have been able to send emails using her actual email address rather than just using her display name to make their scam / spam emails merely appear to come from her.
However, it could well be malware on her device that is stealing the information and sending these emails from a device on her home broadband network. Those scam emails would not show up in her VM email account so she would be unaware it was happening.
If she is using a Microsoft Windows device I would suggest running a full antivirus scan. No AV is guaranteed to catch all Malware so I always think it is best to run a second scan with another product. Malwarebytes. https://www.malwarebytes.com/ is a good option. The download is free and although they do encourage you to take the paid for option you can just keep using the free version for as long as you like.
The other possibility is that it one of her contacts, possibly the original recipient of these emails, has had their email account compromised. Were your partner's emails that are now being sent out by the scammer originally sent to the same person or distribution list? Bear in mind it could have been someone she cc'd into the original email not just the main recipient.
One final point.
Changing the password on her email account was a wise move but I'm sure you realise that it will not stop someone from continuing to send these scam / spam emails because they do not need to know her password to do that. These scam emails may well continue to appear for some time but it definitely does not mean someone is directly accessing her account.
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