Hey, I've been looking everywhere online for this and I can't find an answer.
I'm a Fed player (Vice Admiral) and was casually looking through my crew roster to find I have a Klingon called "KI Agent Soss", who comes up red with a Klingon rank. There is no mention of it anywhere online =/
Who are they and why are the Klingon investigating my ship?
Mail the spy to a KDF alt or sell it on the exchange. (even though a common sci officer practically worthless.)
I remember when my KDF main accidently bought a Fed version of Sterling Renard (the Vorta Security Officer from the Temporal lockbox - love that guy) - I just mailed him to my Fed and eventually opened a KDF version so it all worked out.
BTW for those of you who are curious, Intelligence Agents occasionally come out of Reinforcements DOff packs and minipacks. And no, sadly, they provide no bonus when sent on espionage missions.