The caption

The montage went up on 25 April, with a caption asking whether this was what the revolution had been for. The date helped. Where the phone the caption was written on ended up is anyone's guess. Four people and a phone: 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

• Albertina, the proofreader: She corrects commas for sport. In the caption she'd only change one: the one before the question mark.
• Bento, the resident historian: He explained to everyone what 25 April had been for. Nobody had asked him.
• Clotilde, the carnation seller: She sells carnations outside the newsroom every year. This year she sold more, and doesn't know why.
• Diamantino, the layout designer: He laid out the story about the video next to the one about the parade. He says it was a coincidence, but he smiled.