Taiwanese independent legislator Kao Chin Su-mei has been barred from leaving the country as investigators probe whether her aide took money from China to build a spy network on the island, a development that is bad for her politically even though she has not been detained.

• Prosecutors questioned Kao as a defendant over her aide, Chang Chun-chieh, who is accused of taking Chinese funding to set up an organization in Taiwan in violation of national security law.
• After questioning, prosecutors released Kao without bail but banned her from leaving Taiwan by air or sea while the case continues.
• Two of her paid assistants were already in detention since September on suspicion of tampering with evidence or fleeing, and prosecutors have asked to extend their detention.
• The case adds to Taiwan's growing worries about Chinese infiltration of political offices through staff and funding.

Outlook: The investigation is expected to widen, with more questioning likely as prosecutors build the case against Kao's former aides.