The Evidence Folders

The case file

Four clerks each carried one evidence folder -- red, blue, green, and yellow -- into the courtroom. The sign-in log kept four notes about who carried which color. Who carried the red folder?

The rule: Each clerk carried exactly one folder, and each folder went to exactly one clerk. All four notes are accurate.

The clues

1. The green folder went to Derek Sloane.
2. June Park and Alba Finch received different color families.
3. The yellow folder went to Peter Aldis.
4. Peter Aldis and June Park received different color families.

Who did it?

1. June Park
2. Derek Sloane
3. Peter Aldis
4. Alba Finch

The verdict

Alba Finch

Only Alba Finch can hold the red folder. Not June Park: if June Park carried the red folder, "Peter Aldis and June Park received different color families" could not be true. Not Derek Sloane: the four notes together rule Derek Sloane out. Not Peter Aldis: if Peter Aldis carried the red folder, "The yellow folder went to Peter Aldis" could not be true.