This most likely was payback for exposing someone's offshore holdings, and the response was chosen to send a message: "Do not expose", and was done in such a bald-faced way that this crime's occurrence presupposes the existence of the very corruption needed to facilitate getting away with it, that any investigation would need to uncover.
TL;DR - that a crime like this, which requires corruption to execute and get away with, can happen, presupposes the investigative apparatus is unable to investigate it, with high probability.