A member of my team has just left as their contact was not renewed. I was their line manager. Our IT department has given me access to their emails for business reasons, I.e. in case I need to pick up any tasks. I have discovered that the ex employee has been spending core work time sending offensive emails about me to her friend. Not an isolated incident, they go back for months.
I have a thick skin but these emails are really nasty. Definitely would have been a misconduct offence if employee was still here. Can I mention this if I am asked to provide a reference in future?