Taipei Mayor Chiang Wan-an fired the head of the city's Feitsui Reservoir Administration after a graft investigation moved to prosecutors — bad news for Chiang's clean-government image.

• Lin Yu-yi, the reservoir agency's director, was removed from his post on Friday pending investigation.
• The case started with a tip-off to the city's ethics office, which opened its own inquiry.
• Chiang was briefed on Monday and told investigators to move fast and hard.
• The national Agency Against Corruption has now taken over, suggesting possible criminal charges.

Outlook: The corruption agency's findings will decide whether Lin faces charges, and the case will test Chiang's handling of scandal inside his own administration.