TALLAHASSEE — Former Gov. Charlie Crist calls him "a great patriot.''

Congressional investigators call him "a war profiteer" who walked away with an extra $200 million while providing fuel to American troops in Iraq.

At Florida State University, he is something of a hero — contributing more than a million dollars to athletic programs, the business school and his old fraternity.

Who is Harry Sargeant III?

A plaque at the Pi Kappa Alpha House on campus calls him "the most powerful man no one knows.'' The moniker comes from a 2008 Miami Herald story that noted his friendship with Crist and his wide-ranging business interests.

Sargeant, 55, is a billionaire former Marine fighter pilot, the owner of an oil and asphalt shipping company with global businesses including aviation companies and an oil refinery.

And in the tangled world of Florida politics, Sargeant is a Republican financial powerhouse.

He has long supported Crist while also helping former party chairman Jim Greer, despite the animosity between Greer and Crist since Greer was charged with stealing money from the GOP in 2010. Crist, now a Democrat considering an attempt to return to the Governor's Mansion, says Sargeant remains a close friend.

Campaign finance records show Sargeant has donated more than $1.5 million to Florida politicians and the state Republican Party since 2000, the year Crist ran for education commissioner.

In recent years, Sargeant has made headlines over fuel he supplied to U.S. forces in Iraq. The brother-in-law of the king of Jordan sued Sargeant in Palm Beach and won a $28.8 million verdict for being cut out of a $1.4 billion defense contract that allowed Sargeant to transport fuel through Jordan. (Sargeant is appealing.) A congressional oversight committee called for an investigation of payments to Sargeant's company, and last year auditors for the Department of Defense accused the company of overcharging the Pentagon by hundreds of millions. A federal investigation is ongoing.

Chris Kise, a Tallahassee lawyer who represents Sargeant, says the overcharging accusations came from Democrats who were angry at Sargeant's fundraising for Republicans.

St. Petersburg developer Brent Sembler was a fraternity brother with Sargeant and Crist at FSU. They and other Pikes have bonded over golf, shooting expeditions, ski trips, Las Vegas and FSU football over the 35 years since most of them graduated.

"He's the toughest competitor I know. If there was a poster child for alpha males, it's Harry,'' Sembler said. "He's a close friend and a good guy, I trust him with my life.''

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The Florida Republican Party and Crist are among those who have benefited from a close friendship with Sargeant. During campaigns Crist has frequently used Sargeant's fleet of airplanes to criss-cross the state for events.

As governor in 2007, Crist concluded a trip to Israel with a stop in Jordan and a meeting with King Abdullah II. Sargeant was waiting on the helipad at the king's home to make the introduction when Crist arrived.

Crist asked Sargeant to become finance chair at the state party after he was elected governor in 2006. Sargeant resigned in 2009 shortly before one of his employees was indicted for making illegal campaign contributions to Crist and U.S. Sen. John McCain. The employee, Ala'a al-Ali, was listed as sales coordinator for Sargeant Marine. He remains a fugitive from charges pending in federal court in Los Angeles.

And then there is Greer, the former party chairman who last month pleaded guilty to theft and money laundering charges and will be sentenced March 27.

Records produced by prosecutors in the Greer case two years ago indicate Sargeant was paying Greer $10,000 a month for a 22-month period while Greer was running the party. Sargeant told state investigators that Greer constantly complained about needing money.

Sargeant said he did not expect any service for the payments. When questioned under oath last year, Greer said it was for consulting work on oil issues.

Late in the criminal case, Greer hired Jacksonville defense lawyer Hank Coxe to help negotiate a plea but won't say who is paying the cost. Sargeant is widely suspected of being the benefactor but he has declined to talk about it.

Sargeant's involvement with Greer became the subject of headlines last year when investigators began asking about a 2008 trip to the Bahamas made by Greer, Sargeant, Crist and others. Delmar Johnson, former executive director of the state GOP, says Sargeant brought women who appeared to be prostitutes to the "for men-only'' event.

Crist and others have denied seeing any prostitutes. Sargeant will not respond to questions about the trip or his relationship with Greer.

Crist says he has not talked to Sargeant about Greer or the Bahamas trip.

"He's a patriot, a great friend, he's a very smart man,'' Crist says. "He's done very well in business and he's worked in all of my statewide campaigns.''

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Apart from Florida politics, Sargeant's oil interests have raised questions.

In 2011, a Palm Beach County jury ordered Sargeant to pay $28 million to the brother-in-law of Jordan's King Abdullah II in a contract dispute over oil profits.

He won the wartime fuel contract in 2004 from the Department of Defense after the invasion of Iraq. The civil lawsuit, filed against Sargeant in Palm Beach by Mohammad al Saleh, accused Sargeant of paying bribes to Jordanian officials in return for the contract. Al Saleh said Sargeant dumped him in favor of Marty Martin, a former CIA station chief in Cairo who allegedly arranged the payoff.

At the Palm Beach trial, Sargeant said he served the government under dangerous circumstances, not for money "but because of patriotism. It's part of being a patriot serving your country and not worrying about your wallet.''

In a 2008 letter to Secretary of Defense Robert Gates, Democratic Rep. Henry A. Waxman, chairman of an oversight and government reform committee, called for an investigation to protect the interest of taxpayers. Defense Department auditors found in 2011 that Sargeant had overcharged the Pentagon by about $204 million. Sargeant has filed a claim for more than $60 million additional dollars he says he is owed. All these are pending.

Several news organizations have reported that Sargeant's fuel contracts are being investigated by a federal grand jury looking at possible violations of the Federal Corrupt Practices Act, which forbids the payment of bribes to foreign officials.

Sargeant and some of his friends say the investigations are politically motivated. Kise said critics do not consider the added cost and danger of transporting fuel across Jordan to Iraq. Defense department auditors, in a partially redacted report released last year, said the nonfuel component of the price was in line with other procurements.

"They should have said the reasons we pay extra are because trucks get blown up along the way,'' Kise said. "The No. 1 priority in war time is making sure the company you hired can actually do the job.''

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Sargeant and wife Deborah, 54, live in a $7.5 million oceanfront home in Gulf Stream, an exclusive town of 926 residents just north of Delray Beach in Palm Beach County. They have two children. The 19,000-square-foot mansion has frequently been the scene of GOP fundraisers.

Besides Crist and Sembler, Sargeant's tight group of fraternity brothers includes David Rancourt, a former Tallahassee lobbyist turned land developer; Broward County Judge John "Jay'' Hurley; former Broward Deputy Sheriff Tom Wheeler; and Charlie Barnes, former head of the Seminole Boosters and an adviser to the Pikes in the 1970s.

"I know Harry as a really bright, smart entrepreneur, few people have that kind of talent,'' Hurley said. "He is one of those people like Steve Jobs who can come up with a new device every six months. Harry was always out front in the shipping and oil business.''

Sargeant is frequently accompanied by Martin, the former CIA agent hired to help with the oil transportation business.

"When you are dealing in some of those Middle Eastern countries, you need his expertise,'' noted Sembler. "When he and Harry talk about business, we leave the room.''

Sargeant also likes guns. Lots of guns. Sembler estimates that Sargeant has around 300 guns, including AR-15's, .50-caliber sniper rifles, automatic weapons, pistols and 9mm's.

But Sargeant doesn't like to hunt. On one occasion Sembler and other Pike brothers were invited to a hunting camp for shooting competitions. Sembler loves to hunt deer and elk and was disappointed to learn that they were there during a week when no hunting was allowed.

One of the big unanswered questions for Sargeant and the other Pikes who are all Republicans is whether they'll support Crist if he runs for governor as a Democrat.

"We haven't talked about it,'' said Barnes. "That is the elephant in the room.''

Times researcher Caryn Baird and staff writer Michael Van Sickler contributed to this report.