Two days after Veterans for a Strong America hosted and sold tickets to a foreign policy speech by Republican presidential front-runner Donald Trump on board a retired U.S. battleship, the Associated Press learned that the group has had its nonprofit status revoked by the Internal Revenue Service.

The group hadn't filed tax returns for three years in a row, the IRS said in an Aug.10 letter.

"We disagree with the IRS determination letter," the group's chairman, Joel Arends, told AP. Law requires tax records for nonprofits to be made public, but Arends declined to provide the news outlet with copies of returns to show how much money the group has collected in the past few years and how it spent that money.

Aside from the group's legal status as a nonprofit organization, the actual fundraiser might have violated campaign finance laws, according to AP. Corporations are only allowed to donate up to $2,700 to a presidential campaign, but with over 850 attendees paying $1,000 per ticket, that limit seems to have been significantly surpassed. Although, the group did say that the proceeds would help pay for event costs as well as support the organization, notes the Daily Caller.

Further, U.S. law "generally prohibits candidates from coordinating their campaign activities with outside groups, and prohibits corporations from spending more than a minimal amount announcing their endorsements," AP said.

Arends and Trump's campaign told the AP they believe no laws were violated. "The FEC has ruled that a candidate may attend, speak at, and be a featured guest at such events," the Trump campaign said in a statement.

Arends said that top national election law attorneys advised his group that the Supreme Court's Citizens United ruling removed restrictions on such endorsements.

Meanwhile, some are beginning to question whether Veterans for a Strong America is even a real organization.

MSNBC host Rachel Maddow pointed out that the group's PAC filings with the Federal Election Commission show it has $30 cash in hand $318 in debts, and the only member of the organization is Arends.

"Donald Trump was not in the military, but he did use a pretty military backdrop tonight to raise money for a non-existent veterans' group, which endorsed him formally as part of his introduction - and he said they have hundreds of thousands of members," Maddow said, reports Raw Story. "And they don't. And so the whole thing is fake."

"I'm sure that in that moment, Donald Trump was very grateful to have that statement of support from this group. But Veterans For A Strong America really does appear to be just one guy," she added.