Bill de Blasio, mayor of New York City, scrapped his White House bid on Friday, Sept. 20, leaving persistent questions surrounding his fundraising practices.

The Federal Election Commission (FEC) sent a letter to de Blasio’s presidential campaign committee, doubling down the ambiguity of his tangled web of money and donors, which prompted at least two formal complaints from watchdog groups during the campaign.

The FEC requested information about a $52,852 debt to de Blasio state political action committee (PAC) controlled by the mayor. The campaign had contended that this was a permissible loan but FEC said that the practice is not allowed by campaign finance rules.

The FEC’s senior campaign finance analyst, Robin Kelly also noted that contributions over $5,000 are barred, meaning that the campaign took more than 10 times the permissible amount from the state PAC and used it for travel expenses, digital advertising, and rent.

The federal and state political action committees, called NY Fairness PAC and Fairness PAC launched last year by de Blasio to support political campaigns of progressive Democrats and fund exploratory efforts for his own presidential run.

However, The City reported that the two PAC have allocated just 16% of their spending in the last year toward Democratic candidates or committees, the remaining was spent for de Blasio’s presidential campaign.

Last month, the Campaign Legal Center filed a complaint with the FEC, calling for an “immediate investigation.” The complaint found donors who had already donated the maximum contribution to de Blasio’s presidential campaign were also giving to both of his PACs.

“[The campaign] appears to have concocted a shell game to arrange for a small number of wealthy donors to support de Blasio’s presidential run above and beyond legal contribution limits,” the group’s complaint said.

De Blasio’s Campaign for One New York nonprofit in 2014 also faced scrutiny and became the subject of the Justice Department. The investigation ended without charges but noted that de Blasio and his aides had supported certain donors.