Regulatory Capture refers to the capture and corruption of regulatory agencies by the interests they are intended to regulate.
The term ‘regulatory capture’ [has] a broad and a narrow interpretation. According to the broad interpretation, regulatory capture is the process through which special interests affect state intervention in any of its forms, which can include areas as diverse as the setting of taxes, the choice of foreign or monetary policy, or the legislation affecting R&D. According to the narrow interpretation, regulatory capture is specifically the process through which regulated monopolies end up manipulating the state agencies that are supposed to control them. 
Gamekeeper turns poacher or, at least, helps poacher. The theory of regulatory capture was set out by Richard Posner, an economist and lawyer at the University of Chicago, who argued that “REGULATION is not about the public interest at all, but is a process, by which interest groups seek to promote their private interest ... Over time, regulatory agencies come to be dominated by the industries regulated.” Most economists are less extreme, arguing that regulation often does good but is always at RISK of being captured by the regulated firms.