The Plumbers, who were members of President Richard Nixon's covert special investigation unit, were tied to President Nixon because he was responsible for approving the creation of the group. The group used less than moral tactics to obtain information from adversaries of the president, including the Democratic Party.
The group was nicknamed the Plumbers because they were created to stop and seal off any media leaks that could be detrimental to the goals of President Nixon. They were initially created to do whatever they could to stop these leaks, but quickly became a group of political people who would break laws and carry out illegal tasks in order to get information. It was not uncommon for the Plumbers to perform burglaries, break-ins and plantation of surveillance devices.
When pertinent information was leaked out of the White House or the political powers who held the information, the Plumbers would be responsible for getting the information back. They would often break into offices and homes to obtain information. They would also implant surveillance devices into the lives of anyone who they, or President Nixon, believed was suspicious of leaking information to the media. The initial doings of the plumbers is generally referred to as the seminal Watergate episode because it occurred before the true Watergate incident.