The campaign committee of Rep. Maxine Waters (D., Calif.) is $88,000 in debt to her daughter for payments to run a lucrative slate mailer operation that has been used by the congresswoman to pull in hundreds of thousands in funds from other liberal political committees.

Karen Waters, the daughter of Rep. Waters, and her firm have been paid more than $650,000 to run the slate mailer operation since its inception, the Washington Free Beacon previously reported. Karen has been on the payroll of Citizens for Waters, her mother's campaign committee, since 2006.

The October quarterly report for Citizens for Waters, which covers finances from the beginning of July to the end of September, shows that the Waters campaign currently has debts of $124,201.69. A majority of this amount—$88,000—is owed to her daughter for her work with the mailers.

Karen Waters received three payments from the campaign committee during the last quarter. Karen was paid $4,362 on August 2, $3,000 on September 8, and $4,000 on September 19.

Karen is in charge of endorsement mailers, or "slate mailers", for her mother's campaign, an operation that has pulled in hundreds of thousands of dollars for the committee in recent years.

Candidates must pay Citizens for Waters from their own campaign committees to appear on the slate mailer. If a candidate running for political office does not directly pay Waters' campaign committee, they must credit their own campaigns with in-kind contributions from Waters.

The slate mailers are sent to nearly 200,000 constituents in the South Central Los Angeles region, where Rep. Waters has considerable clout. The mailers consist of an "official sample ballot" with quotes from Waters about the candidates and issues that she supports.

During the 2016 election cycle, Waters received nearly 20 payments totaling $300,000 for the slate mailer endorsements.

Sen. Kamala Harris (D., Calif.) has given the Waters campaign $63,000 to appear on the endorsement mailer during the 2010 and 2016 election cycles, the Free Beacon reported.

As Harris was running for attorney general in California during the 2010 election cycle, her campaign made three payments totaling $33,000 to Waters for to appear on the endorsement mailer. As Harris was running for Senate in 2016, she paid the Waters campaign another $30,000 to again appear on the mailer.

Karen, who first began receiving payments from her mother's campaign in 2006, previously ran the operation from a state committee called LA Vote.

In late 2004, the Federal Election Commission issued an advisory opinion that allowed Waters to run the slate mailer operation from her federal campaign committee.

Slate mailers operations, which have come under heavy scrutiny, are fairly common in the states of California and Oregon. However, Waters appears to be the only member of Congress to run a slate mailer operation from their federal committee.

Waters's office did not return a request for comment on the payments by press time.