A stop at the service station

Halfway to the stadium, the referee's car stopped at a service station. He filled up, ate and drove on, but the whistle didn't go with him. The clues no longer hand you everything on a plate.

Suspects

• Adriano, the lorry driver: He always stops at the same service station. He knows every referee by their car.
• Berta, the shop assistant: She sells chewing gum, newspapers and coffee. She also sells silence, but that doesn't go through the till.
• César, the referee's driver: He drives the referee everywhere. He always stops here 'to fill up', even with a full tank.
• Diana, the restaurant cook: She makes pork rolls for travellers from north and south. She hears conversations going both ways.