@staika: Don't worry about it. We all have lapses in judgment sometimes. Plus, it's very possible the killer already knows that person's identity seeing the confusion that we are currently caught in.
The thing that interests me most about this is the fact that Steke didn't provide us with any questions while the person claiming to be the spy did. It's also interesting to note that the person who Steke is claiming is the killer was also on the spy's list and that Steke has just been removed from the spy's list, meaning that he just received that message earlier this morning as well..
It makes a person wonder if the person claiming to be Steke's spy is also on that list. If so, then we've got something really memorable on our hands. >
So, my recommendation would be to go with Steke's suggestion since it's already a match with the list. If he's correct, no problems. If he isn't, then he needs to release more information about who his co-conspirators are. I have reason to believe that one of them is the killer.