@Genevieve37 maybe ABB would give ID info to the police if police contact them.. but somehow I doubt it 😞
In future, my advice is, ask your guests to show you their ID. Look at the photo, look at their faces if it is the same person.
Make a photo of their ID or print a form at home and fill it infront of them:
Date when they checked in and when they should check out
Name and surname
Gender
Number of ID card /passport/driving license
Citizenship
Town of residence
Country of birth
Date of birth
At the bottom writte how many keys you gave them and that they should return them on check out.
When you are finished with filling the form let them sign it.
In case of any problems you will be able to tell police their names and other data.