The missing thirty seconds

The radio station had recorded the whole concert. When they went to listen, the most famous thirty seconds in the country were missing, along with the microphone that recorded them. Some clues in this case come as riddles. If one stumps you, a hint will solve it. Not every row and column has to be occupied.

Suspects

• Alberto, the editing technician: He edited the whole concert. He says the thirty seconds were left on the editing desk, and the desk isn't talking.
• Blandina, the station archivist: She has kept every recording since 1986. This is the first one anyone has asked for.
• Ciro, the programme director: He wants to play the thirty seconds every hour on the hour. He hasn't found them yet.
• Dagmar, the intern: She heard the thirty seconds live and says she knows them by heart. She sings them to anyone who asks.