In the pay of somebody/something
Definition 1 of 1
Pro Tip 1/3Connotation of Corruption
This phrase often implies that the person is being influenced unethically by money. 
The journalist denied being in the pay of the tycoon, despite rumors.
Pro Tip 2/3Suspect Loyalties
It suggests the person's loyalties may be compromised due to monetary gain. 
Is the referee in the pay of the home team? That call was suspicious!
Pro Tip 3/3Secret Arrangements
The phrase is used when payment or agreements are often secretive or not publicly disclosed. 
The agent was in the pay of the foreign government, working undercover.