The trailer with GPS

The seized trailer had GPS. The GPS says the trailer spent the summer in a builder's warehouse. The trailer has no comment. Some clues in this case come as riddles. Four people and one piece of evidence: 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

• Aníbal, the builder: He swears the trailer turned up in his warehouse by itself. He thinks it walked there.
• Brites, the police officer: She seized the trailer in March. In April she seized it again, in the same place.
• Cipriano, the tow truck driver: He tows whatever he's told and doesn't ask where to. He never has.
• Delfim, the GPS technician: He fitted a GPS to the trailer. The GPS says the trailer went on holiday.