Three codes were hidden in the HTML source of the CHICAGO RPE REPORT 1 post on the Investigate Ingress blog.
[1] ie5e5842mdvjnepfd
[2] au3zergudkilstael
[3] ewmtjq848433574aw
Code #1, #2, #3
Observations
All three codes have the same length and the total amount of number is 15, all you need for 3 valid passcodes