HONG KONG — Many explanations have been put forward to explain why Hong Kong, a city famous for its orderly ways, has been convulsed by nine weeks of increasingly violent protests.

The most immediate is fury at a proposed law that would have allowed extradition to mainland China. There is also anger at astronomical property prices fueled by wealthy buyers from mainland China, and revulsion at heavy-handed police tactics involving the regular use of tear gas and rubber bullets.

On Thursday, however, China’s ruling Communist Party identified a novel reason for the unrest: the secret machinations of an American woman working as a diplomat in the United States Consulate in Hong Kong.

The woman, Julie Eadeh, a political counselor, has become a central figure in a growing Chinese narrative that Hong Kong’s protests are the work of traitors who are being directed by foreign, particularly American, “black hands” bent on fomenting an uprising in the former British colony.