Actually they can't tell them apart all of them are a bunch of hypocrites.
But..., I wouldn't be suprised if there is another chapter in which Chris actually knew It's Noizu and is a more twisted :V. Omg I should stop reading these types of manga my mind is going wild.
You think they would go through the trouble of like genetically telling them apart lol.
Okay, why were they so certain who died and who lived, like did they want him to be the one to die and that's why they assumed it was him?