The delay

At home, the anthem arrived half a second after the singers' mouths, and half a second in an anthem is an eternity. At the racetrack nobody noticed a thing. Somewhere between the two, the right sound got lost, and so did the earpiece. Four people and an earpiece: one person per row, one per column. Whoever is left alone with it in the same room is the one you're looking for.

Suspects

• Abílio, the track marshal: He waves flags. There was no right flag for the anthem, so he waved the green one.
• Belisa, the motorsport journalist: She wrote the race report and one line about the anthem. The line got more readers.
• Cassiano, the satellite technician: He makes sure the signal leaves on time. He admits the sound sometimes catches the next bus.
• Delmira, the official timekeeper: She measures everything to the thousandth. She timed the anthem's delay at half a second and a grimace.