PETA -- the most obvious suspect in the Kim Kardashian flour bomb attack -- is adamant the organization is NOT behind the red carpet stunt ... but it's VERY SUPPORTIVE of the attacker.
A rep for the People for the Ethical Treatment of Animals tells TMZ ... "It was not [us]. We were given the video by an anti-fur activist on the scene."
Still, a rep for the organization explains, "PETA has tried everything from polite letters to public protests, but Kim Kardashian has not been moved by the news that animals are beaten, electrocuted, and even skinned alive for real fur garments. Whoever threw that flour may reach her when our polite appeals did not."
As we previously reported, Kim was flour bombed on the red carpet of a Hollywood event last night ... while the mystery attacker lady shouted, "Fur Hag!"