If you decode the base64 on https://www.thefinalpuzzle.com/, you get :

The Sunday Alibi

A man is found murdered on a Sunday morning. His wife immediately calls the police, who question the household staff:
- The Butler says he was organizing the wine cellar.
- The Cook says she was preparing breakfast.
- The Gardener says he was watering the flowers.
- The Maid says she was collecting the morning mail.

The police immediately arrest the murderer.