The trailer with a new face

The seized trailer turned up again, this time with a new number plate, a new paint job and the same dent in the door. Some clues in this case come as riddles. If one stumps you, a hint will solve it. 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

• Armando, the car painter: He painted the trailer blue. The customer asked for something discreet.
• Benilde, the GNR officer: She recognised the trailer by the dent. She says you can't paint over a dent.
• Caio, the impound yard manager: He has forty seized trailers. He counted them yesterday and there were thirty-nine.
• Domitília, the warehouse neighbour: She saw the trailer leave at three in the morning. She thought it was off on holiday again.