Speculation was intense that the Russian Mafia in District 15, Moscow were laundering money via China to invest in London property.

Two names were on the radar. The Russian Taras Petrov and Chinese businessman Xi Lang. 

If the full facts about these two were known to Sarah Petri she would have probably refused to seduce Xi Lang as a means for her and Hacket to infiltrate the Russian/Chinese syndicate.

The problem was that many involved wanted a cut of the dirty funds but did not appreciate the price they would have to pay.