The Service Employees International Union has suspended Executive Vice President Scott Courtney, one of the lead architects of its $15 minimum wage campaign, stating that he violated the union's ethics rules regarding nepotism.

"Questions were raised around Executive Vice President Courtney relating to our union's ethical code and anti-nepotism policy. As a result, SEIU is now investigating the situation that gave rise to these allegations and cannot comment on specific details of this ongoing investigation. We are taking this investigation very seriously. This investigation started with specific questions around a supervisor-supervisee relationship which, if true, violates our union's standards of ethical conduct for officers. As credible allegations come in, we are pursuing them as part of this investigation," said SEIU spokesman Sahar Wali.

Buzzfeed News reported Thursday that "complaints about Courtney had been an open secret among women." It reported that seven current and former colleagues of Courtney at the union reported that he was known for having sexual relationships with female staffers and subsequently favoring them for promotion. Two said Courtney did not act on complaints of sexual harassment by others under his supervision.

Courtney's official biography on the SEIU website states that "As SEIU's organizing director over the past six years, Courtney helped lead the Fight for $15, sparking a movement that Slate has called 'the most successful progressive political project of the late Obama era, both practically and philosophically.'" He reportedly recently married a union staffer.

A source at SEIU said, "Scott has been suspended from his duties as an officer. Per SEIU's governing documents, that is the highest form of action she can take against him on her own. The executive board has the power to remove him."

The union was the main group involved in staging protests and other events for a $15 minimum wage, according to its Labor Department filings. It poured at least $14 million into the effort in 2016 alone. That includes $3.6 million to the Fast Food Workers Committee, the main group behind the "Fight For $15" movement, as well as nearly $9 million to various regional workers committees engaged in similar activism.

SEIU is one of the few major unions led by a woman. Its president is Mary Kay Henry. A union official could not be reached for comment.

According to the conservative Center for Union Facts, Courtney had an annual compensation of just under $250,000.

• This article has been updated.