Tell your leader to uncheck white list for everyone except 2 seniors for 2 or 3 weeks to see what happen.
If thing really change and there are really spies among your group, slowly check white list and check who is the spy.
BTW if a spy is a clone of someone, this account usually have low level, very casual. Don't even bother to do stuff like daily events, group boss, etc... but still online for couple days in a week or in some case daily. Also rarely speak, rarely ask for TI help and stuff like that but always online on saturday for GNW.