Xiaoyu" and were planning on leaving HTC after receiving their mid-year bonuses. The company caught Chien downloading files relating to the unreleased Sense 6.0 UI which he emailed to a third party. The Taiwan based handset manufacturer's chairwoman Cher Wang reported the incident to Taiwan's Investigation Bureau.
Additionally, the three men split the equivalent of $334,000 USD after scamming HTC out of money by asking an external design house to bill HTC that amount for work that the design house said it performed on the design of the aluminum chassis for the HTC One. The design was actually done in-house.
The story is big news in Taiwan as you can tell from a newscast of the story below.
source: UDN (1), (2) (translated), ChinaNews (translated)