Lindsey Graham, James Clyburn Were Under Scrutiny in FBI Bribery Probe — ProPublica

On March 3, 2020, Sen. Lindsey Graham walked into a private dining room at Charlie Palmer Steak in Washington, D.C. Graham’s time was expensive. He was meeting with two executives and a lobbyist from a Hawaiian naval defense contractor called Navatek. And he had required them to commit to $40,000 in campaign contributions for a 45-minute meeting.

Navatek’s CEO, Martin Kao, was confident that was all the time he needed.

“Shoot all he has to really do is stop by and say ‘yes,’” Kao wrote to a Navatek lobbyist and a fellow executive the day before, in an email seen by ProPublica. “That should only take a minute and he’s on his way. We don’t need to pretend we give a shit about each other.”

At the dinner, Graham ate little and talked a lot. But Kao got the “yes” he was hoping for: Graham agreed to steer a $10 million government contract Navatek’s way in his native South Carolina, Kao later recounted to the FBI. In exchange, he said, Graham asked Kao to pledge a total of $100,000 to his reelection campaign.

In early 2025, the FBI opened a sweeping investigation into bribery on Capitol Hill with Graham’s steakhouse dinner at the center. Kao confessed to federal agents that his business model consisted of bribing public officials in exchange for government contracts, and that the research Navatek was providing to the government was often worthless.

The scheme involved some of the most powerful figures in Congress, he said — in both parties. In South Carolina, Kao told agents, Navatek made a campaign cash-for-contracts deal not only with Graham, but also with the state’s top Democrat, Rep. James Clyburn, and another influential Republican, Rep. Joe Wilson.

Kao told agents that Graham in particular left little room for ambiguity: “This is how much I want, and how much I am going to give you,” Kao remembered Graham saying, according to notes one agent took during their debrief in late 2024.

Kao’s admissions would constitute a vast criminal bribery scheme if they could be proved in court — a challenge, given recent Supreme Court rulings that have made it more difficult to win corruption cases. Kao himself posed another hurdle. He was facing prison for fraud and campaign finance violations and was speaking to the FBI in the hopes of reducing his sentence.

But the FBI agents who took Kao’s confession — two experienced anti-corruption investigators — could see that much of it lined up with a trove of records they had seized from Navatek. They forged ahead. The FBI took the formal step of naming two former Navatek executives who had worked with Kao as subjects of a bribery investigation. The agency did not designate Graham, Clyburn and Wilson that way, but the agents were actively investigating their interactions with Kao. The agents indicated to their superiors that the lawmakers could become subjects in the future, according to records viewed by ProPublica.

The details of this investigation have not previously been reported.

President Donald Trump returned to the White House and almost immediately gutted the specialized FBI and Department of Justice teams dedicated to taking on public corruption — an act of revenge for having previously investigated him. The two experienced agents on the case were swept up in the purge, and the career prosecutor assisting them quit after Trump appointees forbid the DOJ’s anti-corruption section from filing any new cases. Today, there is no one left to look into Kao’s explosive allegations, as the Trump administration has abandoned any pretense of prosecuting public corruption. The case is dead.

ProPublica has unearthed the investigation by reviewing thousands of pages of legal documents, internal company emails, evidence the FBI used to vet Kao’s claims and dozens of interviews with people who saw how Navatek operated, including an eyewitness to Graham and Kao’s secret steakhouse dinner.

This story is part of a series based on our reporting. Last month, ProPublica reported that the FBI had probed the conduct of Maine Sen. Susan Collins, who steered millions in government funding toward Navatek while Kao gave her illegal campaign donations. Collins denied wrongdoing and dismissed Kao as a “convicted liar.”

Kao is indeed the only person involved to serve prison time. He pleaded guilty to making illegal campaign donations and a loan fraud scheme in 2022. In 2025, he was sentenced to 87 months in prison.

Graham died at 71 earlier this year. His sister, Darline Graham, who was appointed to fill his seat, retained most of his senior staff, including those who dealt with Navatek. She even took up some of his committee assignments, including appropriations. Darline Graham is running for a full term in office this November.

Clyburn, 86, is one of the most powerful Democrats in Washington. He is widely credited with tipping the scales for Joe Biden during the 2020 Democratic presidential primary. Wilson remains influential on national defense spending from his senior perch on the Armed Services Committee.

“Whatever a donor may think or say, a donation would never cause Congressman Clyburn to increase his support for the donor’s request,” Jami LaRue, Clyburn’s communications director, wrote in response to detailed questions. “The Congressman has always striven to assist the University of South Carolina and all of the colleges and universities in his district when called upon to further their important missions. The crimes and lies of an imprisoned fraudster will not cause the Congressman to waver in his support for these fine institutions.”

David Snider, Wilson’s communications director, did not address a detailed list of questions sent by ProPublica. “Congressman Wilson does and has always abided by campaign donation regulations set forth by the Federal Election Commission,” Snider said in an email.

In an emailed statement, Taylor Reidy, who was Lindsey Graham’s communications director and now holds the same post for his sister, wrote that “any allegations of quid-pro-quo behavior or wrongdoing by the late Senator Lindsey Graham or his staff are simply false.” She said the accusations were the “ravings of a convicted felon” and that her office was never contacted by the FBI about the matter. After Kao’s arrest, they disgorged his donations, she added.

The two executives who were subjects of the FBI investigation, Duke Hartman and Joshua Knight, were never charged. Hartman, the other executive at the dinner meeting with Graham, is now the CEO of a new naval research company called Integer Technologies that he co-founded with Knight after Kao’s arrest. Integer was recently recognized as one of the fastest-growing government contractors in the country. It also became the ultimate beneficiary of the Graham dinner meeting, picking up the contract Graham allegedly agreed to facilitate that night.

Hartman and Knight did not respond to detailed requests for comment.

“[It’s] corruption at its best,” Kao wrote to ProPublica from federal detention in South Dakota, before cutting off contact. “But I am the only one rotting in prison.”

Small Company, Big Ambitions

Kao’s dinner with Graham was part of his grandiose plan to make Navatek a major defense contractor.

He had become the CEO at an uncertain moment in the company’s history. Founded in Hawaii in the 1970s, the company originally thrived on a close relationship with the state’s powerful senior senator, Daniel Inouye. When Kao assumed ownership in 2019, it had been several years since Inouye had died, and Navatek was in need of a new patron in Washington.

At times, Kao hardly seemed the person to pull this off. He had started out as the company’s CFO and was openly uninterested in its technology. He told bombastic lies about his personal life. Former employees said he regaled them with tales of selling newspapers for members of the Bloods and Crips street gangs as a youth. In a deposition, Kao later admitted that wasn’t true.

But what he lacked in engineering chops he made up with ambition. Once, Kao held a company town hall using a map of the U.S. dotted with future Navatek offices as his backdrop, a former employee recalled. “He would talk about how we’re a $10 million company, and in the next three years, we’re going to be a billion-dollar company,” said a former engineer. “He was an absolute megalomaniac.”

Kao hatched a plan to expand Navatek’s presence across the country, making new friends in Congress along the way. He courted politicians using something he called “the method,” as ProPublica detailed in September.

Navatek would open an office in the state or district of a powerful member of Congress and partner with a local university to concoct a proposal for federally funded research. Then, aided by a well-connected lobbyist and the sheen of credibility from its association with the university, Navatek would approach the member for federal research funding.

Kao told the FBI he would strike deals in small, face-to-face meetings with the members or their trusted staff. Navatek — through executives, family members and lobbyists — would make generous campaign donations. In exchange, the member would add detailed language to the defense budget to fund the company’s work.

That legislative language would not name the company. But it would describe specific work that Navatek was already planning to do behind the scenes, making it the only logical choice for the eventual government contract. The lawmakers’ staff would also backchannel with the Navy after the bill was passed to make sure contracting offices knew to direct the money to Navatek, emails seen by ProPublica show — even though the contracts were in theory competitive.

Kao “wanted to build a company as big as he could as fast as he could,” a former executive later testified in court. For a while, he succeeded. Under Kao, Navatek went from having to “rebuild,” as the executive put it, to winning $40.7 million in new government contracts in 2020.

Hartman, the other Navatek executive who went to dinner with Graham, was in charge of maintaining friendly ties in Congress while tracking the millions of dollars the company had requested in research funds. He kept careful tabs on the company’s progress using dozens of color-coded spreadsheets. “If anyone knows the impropriety of the business model, it’s him,” Kao told the FBI, referring to Hartman.

Later, these spreadsheets provided the FBI a detailed picture of which congressional offices worked closest with Navatek. In the tables devoted to South Carolina, Navatek denoted Graham as a “key supporter.”

The company primarily targeted lawmakers from smaller states who sat on appropriations committees, like Collins, Kao explained to the FBI, because they wielded huge power over the budget while having fewer “constituents to ‘feed.’”

The senior senator from South Carolina was another prime target. “You can get access to Lindsey Graham,” Eric Schiff, a former Navatek executive, said in an interview.

Kao, Hartman and other Navatek executives approached the offices of Graham, Clyburn and Wilson — all powerful members of the South Carolina delegation — in the beginning of 2019. The company had recruited the University of South Carolina for a joint research project, and together they asked the lawmakers to find $9.5 million to fund the work. If it succeeded, Navatek planned to ask Congress to re-up the funding for two more years as well as green-light two more projects, internal company records show, for a total of up to $90 million in South Carolina alone.

Yet Navatek had “zero people” capable of doing the research it was pitching, said a former executive with direct knowledge of the work.

Its $9.5 million “power and energy” proposal promised cutting-edge research on how to distribute the limited power on board a ship between multiple energy-intense systems, like radars, lasers and rail guns. Graham’s office later boasted that the work would lead to new technology that would “ensure that our fleet is ready for the fights of the future.”

In reality, Navatek’s initial research “looked like a college senior’s graduation project,” the executive said. “Something you go get from RadioShack.” Graham’s office referred questions about the quality of the work to the Navy and the university. The Office of Naval Research, which awarded the contract, did not respond to questions.

But for Congress, that lack of expertise wasn’t a problem. Throughout 2019, the FBI noted, as the ensuing year’s budget came together, both Graham’s and Clyburn’s offices took steps to make sure it included Navatek’s funding.

In May 2019, Willie Lyles III, Clyburn’s legislative director, alerted Navatek that the House Appropriations Committee would endorse new funding for a “modular and scalable integrated power and thermal system capable of powering a directed energy weapon system of 100 or more kilowatts,” according to an email flagged by the FBI. Three days later, that exact language appeared in the House Appropriations Committee report. Lyles did not reply to a request for comment.

In September, the Senate Appropriations Committee — Graham’s committee — released a budget report that set aside $9.5 million in funding for “Talent and Technology for Navy Power and Energy Systems.” Agents noted that Navatek may have ghostwritten the technical description that accompanied this line item because “an almost identical paragraph” appeared in Hartman’s internal spreadsheets two months before the Senate report became public.

After the Senate advanced its version of the budget in the fall, Navatek dropped $4,799 to send bourbon to a handful of lawmakers, including Graham and Collins, the FBI found in company records — a likely violation of Senate gift rules. Both Collins’ and Graham’s offices denied receiving bourbon. Navatek later sent Clyburn a fruit basket from Edible Arrangements for $102.60.

Congress passed the final spending bill containing $9.5 million for Navatek’s pet project on Dec. 19, 2019.

At that point, Kao and other Navatek executives had not made any donations to Clyburn, Wilson or even Graham.

That would change within days of Congress passing the budget, when an executive pledged $750 to Wilson’s campaign at a fundraiser held at Bullfeathers, a Capitol Hill watering hole for lobbyists and Hill staffers, emails show. In the following weeks, Kao and his lobbyist gave Wilson’s campaign $3,500.

And bigger checks were imminent. Kao kicked off 2020 by making plans to spend $300,000 at a slew of political fundraisers, according to text messages filed in court and a recent deposition. Navatek’s lobbyists at that time were seeking private meetings with Graham, Wilson and Clyburn, where Kao planned to ask for significantly more federal funding. Kao eventually met with all three, and each asked for $100,000, he told the FBI.

During that same period, Kao and Hartman met a top fundraiser for Collins at a Corner Bakery in Washington, D.C. As ProPublica reported, that meeting led Kao to donate $150,000 to the pro-Collins super PAC. Kao told the FBI that the money was a bribe in exchange for the senator’s support for more Navatek funding. The head of the super PAC and Collins have denied Kao’s version of events.

Kao told the FBI it was not unusual for donations to come after the favor: “We became clever in our own right and figured out how to dangle the carrot,” he wrote in a memo seen by ProPublica, “until we saw some assurance that the Ask was in the budget.”

To secure a meeting with Graham, Kao hired Michael Tongour, a veteran South Carolina lobbyist who was old law school friends with the senator and family friends with Clyburn and Wilson. Graham was up for reelection against a well-funded challenger, Jaime Harrison, and had a crowded fundraising schedule, said Tongour, but they eventually found a time.

“The Graham fundraiser says that it [sic] you want to reserve a date for Senator Graham to attend a private dinner, the campaign wants to get $40,000 in contributions,” Tongour wrote to Kao, Hartman and lobbyist Andy Winer, in an undated email seen by ProPublica. Winer, whom Kao described as Navatek’s chief lobbyist, chimed in to say that Graham could stay only 45 minutes, and Kao replied that all they needed to hear was “yes.”

“These discussions are very frank and oddly not at all awkward,” Kao told the FBI. “I suppose once we got that far, everyone knows the deal.”

A Dinner With Graham

Graham showed up late to his March 3, 2020, dinner with Kao, Hartman and Tongour. A fundraiser working for Graham appeared first and accepted an envelope from Kao containing checks made out to Graham’s campaign, Kao said. Kao did not know the fundraiser’s name; in an FBI debrief, he simply referred to the person as the “money man.” After that person departed, Graham entered.

Graham, Kao recalled to the FBI, was “very abrupt” and “straight to the point”: He asked how much Navatek wanted, to which they said $10 million a year for three years. Graham asked Kao to pledge $100,000 in donations in exchange for his support, Kao told the FBI.

Navatek was juggling multiple proposals in South Carolina worth around $10 million, and it’s not clear which one Kao was describing.

Congress had just approved the $9.5 million for the power and energy project, but Navatek still needed the Navy to award the money in the form of a contract. The company was also about to ask Congress to fund the same project for a second year at $10.5 million. On top of that, Navatek was planning to pitch a new research proposal, at $10 million, to study the transport of supplies inland from ships using autonomous vehicles. It was another area where Navatek had “zero past performance,” the former executive said.

The same week of the steakhouse dinner, Graham’s office was working behind the scenes with Navatek and the University of South Carolina to make sure the Navy sent the first $9.5 million to the right company.

A day before the dinner, an official with the Office of Naval Research emailed Graham’s office to ask about the money, which “the Senator may have an interest in.” Craig Abele, Graham’s national security adviser, called her a few days later to confirm that Graham’s office had intended the money to be awarded to the Navatek partnership, emails show. “Spoke to ONR this morning,” Abele wrote March 6. “Should be set.”

The company received the contract, which it split with the university, in July 2020. 

Abele became Graham’s deputy chief of staff and still holds the position for Darline. He did not reply to an email requesting comment. A Graham spokesperson confirmed to ProPublica that their office had indeed added the $9.5 million to the budget at the request of the university and Navatek. The spokesperson said the research was supported by the Navy and rejected the notion that Graham was motivated by campaign cash.

Graham’s spokesperson said requiring a fundraising minimum for a dinner was normal practice.

“[It’s] corruption at its best. But I am the only one rotting in prison.”

Former Navatek CEO Martin Kao

The checks Kao handed over at the dinner added up to about half of the $40,000 he had agreed to raise for the dinner, according to Tongour. The rest came in May, campaign records show.

“My understanding at the time was that the contributions associated with the event were lawful political contributions,” Winer said. “I never advised Kao to make a political contribution in exchange for official action. I never participated in, witnessed or had knowledge of any illegal political contribution.”

After Kao’s 2020 indictment, the University of South Carolina broke off the partnership. “University officials were not aware of any political contributions from Navatek,” Jeff Stensland, a university spokesperson, wrote in an email. “Our sole objective in partnering with them was to expand our research enterprise.”

One week after the dinner, on March 10, a University of South Carolina lobbyist sent written requests to Graham’s office for $20.5 million in appropriations: $10.5 million to continue Navatek’s power and energy research and $10 million for its new autonomous vehicle research.

Tongour confirmed many elements of Kao’s story. In a recent interview with ProPublica and subsequent emails, he remembered Kao giving the envelope full of checks to Graham’s fundraiser and even agreed that Graham kept the meeting short. “I don’t recall that he stayed more than 30 minutes,” Tongour said in an email. “Certainly not for appetizers, entrée, and dessert.”

But he denied Kao’s most significant claim: that Graham and Navatek struck an explicit, potentially illegal deal for contracts.

“I would remember that forever,” Tongour said. Graham supported Navatek’s requests, he said, because they were good for the state. “If I had seen that kind of quid pro quo, I would have quit earlier.” Tongour fired Navatek as a client later that year, immediately after Kao’s arrest.

Navatek considered Graham its chief patron in South Carolina, internal records show, just as it viewed Collins in Maine. But the company also wanted support in the House.

For that, Navatek turned to Clyburn, a member of Democratic party leadership and one of the most powerful figures in Congress. Agents found Navatek emails setting a meeting with Clyburn for early March. The goal, Kao said, was to make sure that the House draft of the budget “mirrored” whatever Graham inserted in the Senate version.

Over a meal, Clyburn asked Kao how much he was donating to Graham and then asked for the same amount, $100,000, Kao told the FBI.

The FBI tallied $20,000 in contributions that Kao and his family members made to Clyburn a few days after their scheduled meeting. A month later, Hartman arranged for a $10,000 gift to Clyburn’s alma mater, South Carolina State University, according to an email seen by ProPublica. Hartman noted it was “Congressman Clyburn’s favorite school.”

The spokesperson for Clyburn confirmed the dinner occurred but did not respond to questions about what was discussed.

Kao and Hartman struck a similar bargain with Wilson, Kao told the FBI, at a private lunch he secured by donating to his campaign. The FBI pulled records of $3,500 in donations Kao and Tongour made in late 2019 and early 2020.

Wilson has an influential role on the House Armed Services Committee, which authorizes defense spending. Wilson was “very clear and knew what the ask was,” Kao told the FBI. He wanted however much Clyburn was getting in campaign contributions in exchange for his support, Kao said.

Tongour denied this. “There was no ‘pay to play’ with Joe Wilson or his staff either,” he wrote in an email, adding that he donated because Wilson “is a friend and I want to see him re-elected.”

Kao claimed to the FBI that he paid for meals with all three politicians, but campaign finance records appear to show the lawmakers’ campaigns picked up the check.

By August 2020, Hartman had gotten word that Graham’s and Wilson’s committees would each support part of the company’s requests, internal company records show. Clyburn was not on key committees while he was a party leader. In one of his myriad spreadsheets, Hartman projected that the final budget could include up to $15.5 million of the $20.5 million the company had lobbied for.

Kao told agents he was gearing up to make more significant donations to Graham, Clyburn and Wilson by the end of the year. Instead, on Sept. 30, 2020, he was arrested.

Kao reflected on his time at Navatek in a deposition taken last month inside a federal prison. The company’s founder has sued Kao, saying his stewardship defrauded Navatek of millions.

“It’s nothing more than government contracting done through placating senior appropriation members for contracts,” Kao said. “The whole thing is a grand lie.”

An Arrest, a Lifeboat

Kao’s arrest plunged Navatek into disarray. Federal prosecutors charged him with defrauding a federal loan program; not long after, he was also charged with making illegal donations to the Collins campaign and super PAC. Lobbyists, universities and congressional offices abruptly cut off contact. “Don’t call us,” one congressional office told an executive, he later testified.

The Collins campaign said it disgorged Kao’s contribution. Yet the senator, facing a tight reelection bid, has had to field questions following the ProPublica report about her support for Navatek and why the super PAC supporting her accepted the $150,000 donation from the shell company in the first place.

As Navatek sank, Hartman began building himself a lifeboat. In 2021, he and Knight started a new military research company headquartered in South Carolina called Integer Technologies. Integer’s first project was one that Navatek had brokered with Graham.

Hartman didn’t face any criminal charges at the time and left Navatek largely unscathed. He would later settle a civil lawsuit brought by his former employer, which contended he played a role in Kao’s campaign finance and loan fraud schemes, for $425,000. He admitted no wrongdoing.

In September 2024, FBI agents flew to Hawaii for what would be their final interview with Kao. They pressed him for details about what happened in South Carolina, quizzing him on his dinner with Graham and a second in-person meeting he said he had with Clyburn. Agents wanted Kao to help them find more records that would back up his account and asked him to point them toward lobbyists in D.C. who he said facilitated the pay-for-play scheme.

As the year came to a close, FBI agent Michelle Ball felt she had enough material to move forward. The FBI had “uncovered a lengthy history” of a government contractor making donations “in exchange for government contracts,” she wrote in a Dec. 9, 2024, memo viewed by ProPublica.

In federal corruption probes, agents often begin by focusing on lower-level targets with a goal of working their way up to more prominent figures. Ball named Hartman; his business partner, Knight; and their company, Integer, as the formal subjects of the probe, as they prepared to potentially issue subpoenas and gather more evidence. They had Graham, Clyburn and Wilson in their sights. Ball devoted entire sections of the memo to detailing the lawmakers’ conduct. And she flagged the case as a sensitive matter that might implicate politicians in the future.

In the summer of 2024, Kate Fifield, a prosecutor in the Justice Department’s anti-corruption section, had been assigned to join the case. Fifield was wrapping up a high-profile prosecution of a retired Navy admiral who traded a government contract for a future job. Turning her attention to Kao, she and the FBI agents weighed their options. They considered getting high-level approval to deploy undercover agents. Proving an exchange of cash for favors often requires the kind of inconvertible evidence that undercover recordings can provide.

But before the investigation took flight, the new Trump administration began to demolish the Justice Department. The president’s handpicked leaders ordered prosecutors to drop a corruption case against New York Mayor Eric Adams, triggering a wave of resignations in the Public Integrity Section where Fifield worked, and revoked the section’s authority to bring new cases.

Then Trump’s FBI director, Kash Patel, began to purge the anti-corruption unit in the Washington D.C., field office, where many agents had investigated Trump.

Ball was fired in October 2025. Kevin Gounaud, another agent who had been working with her on the investigation, was pushed out in early 2026. Through their lawyer, the agents declined to comment.

The corruption investigation, just launched, suddenly went dark.

The White House referred ProPublica’s questions to the FBI and DOJ. 

The Department of Justice didn’t respond to detailed questions about the investigation. 

“Under President Trump, the Justice Department is rooting out the weaponization, corruption, and institutional rot that ran rampant under Joe Biden’s two-tiered system of justice,” DOJ spokesperson Audrey Cook said.

Kao’s claims are “half baked” and “misleading,” FBI spokesperson Ben Williamson said. “Additionally, as we have said repeatedly, personnel are only removed at this FBI if they have been found to have acted unethically, undermined the mission, or engaged in weaponization of law enforcement.”

Meanwhile, Integer has rapidly expanded. Last year, it reported $81 million in contracts and announced that number would climb to $375 million by 2030. The company inked partnership deals with universities in New Hampshire, Louisiana and Mississippi. The University of South Carolina called its partnership with the firm a “model for public-private success.”

The company continues to forge ties with powerful politicians. In late 2024, Hartman posted a photo of himself with Speaker of the House Mike Johnson on his LinkedIn. “It was great to visit with the Speaker of the House today,” he wrote. “It’s good to know there are people in positions of power who seem to really care for the people they serve.” Johnson’s office did not reply to an email requesting comment. 

The occasion was a new research partnership in Louisiana. Hartman thanked his lobbyist for making it happen.