I am currently in the process of writing a D&D 3.5 scenario for my players, and I'm looking at producing a sort of slow burn mystery for them to solve.
In the earlier stages the party may (or may not) depending upon their actions intercept a coded message as it travels from sender to recipient. The coded message is written in ink on a perfectly ordinary mundane piece of parchment, detect magic reveals no magical auras present.
Now just considering the coded message itself, leaving aside situation and circumstance, and aside from the mundane usage of Decipher Script to decrypt as discussed in Complete Adventurer page 98 and spells of the Divination school presented within the Player's Handbook:
What other magical methods exist in order to gain information as to the plain text? The identity of the sender or would be recipient?
I would largely appreciate any responses sourcing D&D 3.5 material published by WotC, but supplementary by 3rd party publishers is okay too.
P.S. The purpose of asking this is to determine whether I've covered all the bases, rather than in the moment being thrown a curve ball by a player with just the right spell.
Assume up to and including epic levels for player characters, so hiring spellcasters is definitely an option; wish spells and the like I have accounted for. Psionics is limited, though lower-level powers could possibly be sourced. In the city where the adventure takes place, IIRC, there is one psychic warrior of 2nd level and I believe a fighter with the Wild Talent feat.