The PAC’s Weekly Wrap-Up: April 17, 2016 post on the investigation board contains the 3 codes:
4 valid digits and 10 letters, we can also spot parts of ‘blue’ as a probable keyword, hinting at a transposition.
Arrange in a 2×6 rectangle:
Almost there, now reverse every other row:
Read out the columns, resulting in:
Latin numerals at the proper places for digits, according to the passcode format.
As a first step, replace the Latin numerals with digits and the 6 with the Latin numeral:
While VI is a valid keyword, this code doesn’t work.
So, with VI most likely referencing Verum Inveniri, we try keyword substitutions, until we find:
Words for digits appear to be scattered back and forth through the code (two, four, six, three). We should try transpositions again.
Start at the letter f at the very center of the code, then pick the o to the right, the u to the left, the r to right, the o to the left and so on back and forth.
The first line below displays the letters picked from the left side, including the starting f. The letters picked from the right side make up the second line.
f u d e h e o s d a v i j w f
o r e t r e b i i n s x t o
Thus we get:
And replacing words by proper digits: