That immediately defeats the purpose of the "anonymous" detective. If the double agent can instantly pinpoint who this individual is and has means of covertly communicating with the traitors, then how is this any better than the situation you're complaining about? The anonymous detective is just going to be ratted out first thing and then be no better off than the plain and identified detectives. If anything, he's is at a greater disadvantage since regular innocents can't trust him.
Thats the point :paranoid: