Why did Chile kill Wu Zhenyu's son in Crouching Tiger, Hidden Dragon?

The one on the first floor is wrong ... The photo taken by the mobile phone has no evidence to prove that Csillam did anything bad. This photo should have been taken unintentionally. ...

Csillam killed Wu Zhenyu's son for a simple reason: because Csillam lied to the people in the club, he had fled, but when an acquaintance (Wu Zhenyu's son) saw him, his plot was exposed, so he covered his mouth and the photos taken by his mobile phone became a thing of the past.