The lawyer for a missing Chinese journalist says his family has no way of finding him after police and airline officials rejected inquiries of his whereabouts.

Jia Jia, who has been linked by Hong Kong media reports to an anonymous online petition calling for the resignation of Chinese President Xi Jinping, disappeared Tuesday from the Beijing airport on his way to Hong Kong. That's according to his lawyer Yan Xin, who says authorities at the airport, local police, immigration services and the airline have all denied knowledge of his case.

Yan says his client has told friends he had nothing to do with the petition.

Chinese police are required by law to notify family of a detained person within 24 hours unless the case endangers state security.