WASHINGTON – U.S. Rep. Ilhan Omar was 19 years old in 2002 when she first applied for a Hennepin County marriage license with Ahmed Hirsi, a fellow Somali immigrant and "the love of my life."

Though the couple would have three children together, split, and later reconcile, they never legally married until January of 2018. By then Omar represented a state House seat from Minneapolis and was on her way to a historic and ultimately successful run for Congress.

Long-standing questions about her complicated marriage and immigration history have dogged her ever since, never more so than on Thursday when a state campaign finance board revealed that Omar and Hirsi filed joint tax returns in 2014 and 2015 — a period when she was legally married to another man.

The disclosure followed an inquiry sparked by a Republican lawmaker accusing Omar of using cash from her 2016 state House campaign to cover legal costs from her 2017 divorce from Ahmed Nur Said Elmi, a British national she had legally married in 2009 after her breakup with Hirsi.

Although the Minnesota Campaign Finance and Public Disclosure Board cleared Omar in the divorce case, the probe determined that campaign money was used for unrelated legal services pertaining to her joint tax filings with Hirsi. She was ordered to reimburse $1,500 in legal fees used to "correct" her 2014 and 2015 tax returns.

In all, she was assessed $3,469.23 in fines and reimbursements for the tax case and other violations of state campaign finance laws, most of them relating to non-campaign travel costs.

Rep. Ilhan Omar, D-Minn., filed jointly with a man she wasn’t legally married to.

Omar's campaign provided a brief statement Friday from a spokesman in response to inquiries about her tax filings: "All of Rep. Omar's tax filings are fully compliant with all applicable tax law," the statement said. Omar declined an interview request for this story, and the campaign did not furnish copies of the tax returns in question.

But for Omar, who has long been in the sights of the Trump administration and conservative critics, the questions surrounding her faulty tax returns are unlikely to end soon. "Time to get federal IRS officials involved?" wrote conservative commentator Michelle Malkin on social media. "What say you all?"

The Internal Revenue Service allows couples to file joint tax returns only if they are legally married in their states of residence. While some states recognize "common law" marriages, Minnesota does not. Joint filers often end up paying less in income tax than if they filed separately. The agency does not confirm or deny its audits or investigations, so officials would not reveal if they have looked into any past tax filings by Omar, a freshman Democratic House member.

Omar said in an interview last year with the Star Tribune that she and Hirsi, both Muslims, were married in their faith tradition in 2002. They separated in 2008, a year before she legally married Elmi.

Omar said she and Elmi split in 2011, divorced "in our faith tradition," and she reunited with Hirsi soon after. In a 2016 statement, Omar said she and Hirsi were married "in our faith tradition and are raising a family together." Like all families, she continued, "we have had our ups and downs but we are proud to have come through it together."

But according to public records, Elmi and Omar's divorce was not finalized until 2017, and she and Hirsi did not legally wed until January 2018.

Omar was first forced to address her marital history when she was running for the Legislature in 2016. She faced allegations published by a conservative blog that Elmi is her brother, and that she married him so he could obtain legal immigration status.

Omar called the allegations "absolutely false and ridiculous." But part of the legal payments at issue in the Campaign Finance Board's investigation stem from inquiries into Omar's financial records by a "crisis committee" that her campaign formed at that time to respond to the allegations about her and Elmi.

Carla Kjellberg, an attorney doing legal work for Omar and her campaign, was part of the crisis committee. "Ms. Kjellberg and some in the crisis committee believed that the allegations required a response and that they needed to see what was in Rep. Omar's immigration and financial records in order to prepare that response," the campaign board's report states.

Shortly after that, the report says, the St. Louis Park accounting firm Frederick & Rosen Ltd. billed Kjellberg's law office $1,500 "for services for 'Hirsi/Omar 2015 & 2014.' " The report goes on to say that "Ms. Kjellberg stated that there was some personal benefit to Rep. Omar from the services as there was an issue with her tax returns that needed to be corrected regardless of her status as a candidate."

Kjellberg did not return an e-mail seeking comment Friday.

Jeff Sigurdson, executive director of the Campaign Finance and Public Disclosure Board, said the contents of Omar's tax returns were not within the scope of the board's investigation into her campaign spending; he said board staff never saw the returns in question. The board does have the ability to refer legal matters to a county attorney's office if an investigation uncovers possible wrongdoing outside the board's jurisdiction.

"There were no referrals in this case," Sigurdson said.

Chris Wittich, an accountant who specializes in taxes at the Bloomington accounting firm Boyum Barenscheer, said that without seeing the returns it's not possible to say whether any couple saved money by filing jointly. Wittich agreed to discuss tax filing errors generally, and not the Omar situation specifically.

"Filing jointly with the wrong person is really bad news for both of those people," Wittich said. "They have signed up for joint liability."

Don Cochran, an accountant and tax lawyer with his own firm, said if the tax savings is more than 10%, a substantial penalty applies. Misunderstanding a tax law is "not a serious problem," he said, but proof of intent typically brings dramatically higher penalties, he said.

Wittich said good-faith errors are common in tax preparation. And Cochran said that, notwithstanding the ominous warning on tax forms that reads "under the penalty of perjury," tax filers who make mistakes rarely face criminal jeopardy.

"It's difficult to prove, and unusual," Cochran said, again speaking generally. "The IRS doesn't want to prosecute bad judgment."

Staff writer Stephen Montemayor contributed to this report. Patrick.Condon • 202-662-7458 Patrick Coolican • 651-925-5042