Union mediation

Hi all,

ive been asked to answer the following for a study piece:

You receive a letter from the union that represents severalworkers at your site. The letter alleges that several employees hold concerns that they are being bullied.

How do you handle this situation?

i would love to hear how you would handle this please? I was thinking about writing something along the lines of:
- statements from all three
- statements from witnesses/accused
- security footage if appropriate
- historical data
- close out meeting with stakehokders
- performance management put in place if needed

id love to hear some opinions of people more experienced than me please. I feel like I should add more information!

Thank you!
Jo