The Philip A. Hart Democratic Club's donation to Build a Better Michigan cannot be traced in public records and disclosures, in part, because the entity doesn't appear to exist in state or federal corporation records.

There is a federal PAC called the Philip A. Hart Democratic Club that runs bingo games to generate money to fund political activities and shares the same address as the Macomb County Democratic Party. But the club's federal PAC didn't have enough money on hand in June to donate $250,000 to the Whitmer group, records show.

"The Phil Hart Democratic Club made a contribution to the Build A Better Michigan fund from Club funds in an account different from the federal PAC," the club's president, Julie Matuzak, said in a statement to Crain's.

Matuzak, a lobbyist for the American Federation of Teachers and Democratic political operative, did not respond to questions about what kind of legal entity controls the bank account that wrote the $250,000 check to the pro-Whitmer group.

When asked whether the group received a donation from Blue Cross, Matuzak replied: "The PHDC (has) never received any corporate money."

There's no record of a separate not-for-profit organization registered under the same name of Philip A. Hart Democratic Club — named after the mid-20th Century U.S. senator from Michigan — with either the Internal Revenue Service, the Michigan Department of Licensing and Regulatory Affairs or the state Bureau of Elections. The group dissolved a state PAC in 2002, records show.

Progressive Advocacy Trust also is not registered with the IRS as a political organization, but is listed in the pro-Whitmer group's financial disclosure as the "administrative account" of the Ingham County Democratic Party. Whitmer represented Ingham County for 14 years in the Legislature and for six months in 2016 as an interim county prosecutor.

Some of Progressive Advocacy Trust's money can be traced through donations it received from an organization that is legally required to report its political spending. In February, the Michigan Pipe Trades Association, which represents plumbing and pipefitters unions, donated $250,000 to Progressive Advocacy Trust, according to a disclosure report filed with the Federal Election Commission.

Both the Progressive Advocacy Trust and Phil Hart Democratic Club are operating under a "huge gaping hole" in the law that exempts them from disclosing their spending activities or existence because they're affiliated with a county political party, said Craig Mauger, executive director of the Michigan Campaign Finance Network.

"They don't have to file with the IRS and they don't have to file with the state because there's a hole between the two laws," Mauger said.

Progressive Advocacy Trust is exempt from the reporting requirements of other not-for-profit organizations, spokesman Mark Fisk said.

"The Progressive Advocacy Trust chose to participate in Build a Better Michigan's effort because both organizations are non-political organizations that share similar core values," said Fisk, a Democratic political consultant with the East Lansing firm Byrum & Fisk Communications. "The PAT believes — like BBM does — that affordable health care, improving our infrastructure, making sure we have safe drinking water, and repealing the retirement tax need to be priorities."

"Once BBM began its effort in earnest, it was decided we should support it," Fisk added.

Build a Better Michigan, or BBM, is registered with the IRS as a 527 political organization and is headed by Lansing political consultant Mark Burton, Whitmer's former chief of staff.

Burton did not respond to questions about the source of Progressive Advocacy Trust and Philip A. Hart Democratic Club's funds and what type of legal entities made the $550,000 in donations to his group.

Ann Arbor businessman Shri Thanedar, who has poured $10 million of his personal fortune into trying to win the Democratic gubernatorial nomination, said the "untransparent" nature of the money being funneled to the pro-Whitmer group is troubling.

"This gives another way for corporations and the rich to influence a candidate," Thanedar said. "My own money is not tainted."

El-Sayed's campaign spokesman said Whitmer and Build a Better Michigan should "come clean about the dark money sources that they are using to corrupt our Democratic primary."

The Philip A. Hart Democratic Club also has been aggressively involved in the six-candidate Democratic primary for the Macomb County clerk/register of deeds.

The club has sent Macomb County voters multiple mail advertisements attacking state Sen. Steve Bieda of Warren and supporting former state Rep. Fred Miller of Clinton Township.

None of the heavy spending in the county clerk's race has shown up in the group's federal PAC reports with the FEC, meaning it also is likely coming from the same account that donated money to the pro-Whitmer group.

"It's an undemocratic slush fund," said Michael Radtke, campaign manager for Bieda, who has filed a complaint against the Phil Hart Democratic Club with the FEC.