The cameras that don't exist

There isn't a single camera inside. Outside there are, and the footage will be watched very closely. The trouble is that it only shows who went through the front door. Place each person in their room, one per row, one per column, and find out who was left alone with the evidence.

Suspects

• Álvaro, the CCTV technician: He controls the outside cameras. The fact that there are none inside has only struck him as a serious flaw since last week.
• Bárbara, the legal adviser: She reads every contract twice. She always signs on the third read.
• Catarina, the youth wing leader: She leads the party's youth wing with more enthusiasm than the job requires.
• Domingos, the night patrol guard: He's done the night rounds for ten years and swears he has never seen anything odd. Until now.