Boss listening to private convos somehow

If this isn't the page, please refer me to one.
Short version,
Housemate and I work in the same company, different departments.
We have had conversations in her office that have not left that room.
She has had conversations in other parts of her end of the warehouse office that haven't left that room.
Boss is repremanding her and quoting from conversations that he was not included in.
Planting "bugs" is illegal in my country unless you are present.
I've …

boss conversations departments end isn listening office page parts privacy private room version work