"Due to the ongoing investigation of the two VX executives, their contracts are suspended and they are on indefinite leave pending the outcome of the judicial process," said the statement.
"Since (the) company is not involved, we have no access to substantive information about the investigation and hence we are not in a position to comment on the situation," said the statement.
Li Yifei, Vivaki country chair in China, told Campaign China that she would be serving as interim CEO of VX and the agency is now in the process of searching for a replacement for Hui.
She insists that Hui is being investigated because of his "personal conduct", which Vivaki has nothing to do with and has no control over.
"All the operations of VX have been completely legal. We have and will continue to adhere to the local laws and regulations," she said.
She also said the agency's operations have not been affected during this transition period. "VX remains in the capable hands of its senior management team," she said.
In September, Campaign China reported that both Hui and Ye had been interviewed by local police in Southwest China's Chongqing.
