The Midnight Séance

During a Halloween séance, the medium Madame Zara is found dead. The suspects are her assistant Paul, her client Mrs. Smith, and her neighbor Mr. Brown.
The Clues:
- Paul says he was in the storage room, organizing supplies.
- Mrs. Smith says she was in the restroom, freshening up.
- Mr. Brown says he was in his own house, watching TV.
- A crystal ball was shattered next to Madame Zara.
Who is the murderer?