Of course, we know it was colonists. But were the British authorities at the time fooled? Or was it pretty transparent?
Think critically; a bunch of white guys with turkey feathers and some buckskin shirts and hatchets hopped up onto a merchant vessel after marching through the streets with torches, and then didn't kill a single soul as they deliberately and carefully only dumped tea into the harbor, taking care not to destroy the ships or other cargo.
This page offers up a number of contemporary accounts, and none of them seem to peg "Indians" as the primary culprits. It was pretty widely known at the time that this was a civic protest against the recent taxations levied. Contextualize it today, and imagine a bunch of guys disguised as Mexican luchadores marching into the LAX harbor and dropping brand new Lexus convertibles over the side, taking care not to disturb the medicine or Apple laptops in adjacent shipping containers. Would you be fooled?
Piggyback question:
Is it possible that insurance fraud was one of the motivations for the "tea party?"