Thom Tillis, Patrick McHenry, North Carolina GOP used Cambridge Analytica in 2014

Sen. Thom Tillis, Rep. Patrick McHenry and the North Carolina state Republican Party all spent money in 2014 with a company now being investigated for alleged inappropriate or illegal use of Facebook data.

Political data mining firm Cambridge Analytica is under fire for its work for Donald Trump's 2016 campaign, using personal information about Facebook users that the social media company says was obtained fraudulently.

There are also questions about whether Cambridge, where former Trump adviser Steve Bannon was reportedly an investor and board member, violated a U.S. law banning foreign nationals from participating in American political campaigns.

Tillis has denied any wrongdoing and Dallas Woodhouse, executive director of the state Republican Party, called Democratic Party criticism of use of the firm "outrageous conspiracy theories."

McHenry's campaign did not respond to a request for comment.

McClatchy reported that Tillis' campaign spent $130,000 in 2014 and 2015 with Cambridge and the state party spent $215,000 with it those years.

McHenry's campaign reported paying $15,000 to Cambridge.

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David Wilson Brown, the only Democrat running in the 10th Congressional District that McHenry represents, called on McHenry "to explain his connection to Cambridge Analytica and disavow their practices."

"I condemn the actions of this company and vow to run my campaign ethically and transparently," he said.

Cambridge has denied wrongdoing. It suspended its head this week after he boasted of various unsavory services to an undercover reporter for Britain's Channel 4 News.

Published reports allege Cambridge improperly obtained information from 50 million Facebook users to try to influence elections. Trump’s campaign also denies wrongdoing.

State Democratic Party Chair Wayne Goodwin told reporters Tuesday that Tillis and other state Republicans have much to answer for about the work Cambridge performed for them.

“Before there ever was a Trump campaign, it was North Carolina Republicans who helped line the pockets of this shady firm – and allowed it to steal and weaponize personal information to manipulate voters,” Goodwin said at a news conference in Raleigh.

Tillis said in a statement that Cambridge "was one of many vendors that provided limited services during my campaign. However, they were not our digital vendor and they have ceased to be a vendor for my campaign for more than three years."

"My expectation is that all services provided to my campaign are lawful – regardless of who provides them, including third parties. If we were misled by a vendor, that would be deeply disturbing,” Tillis said.

No one as yet has publicly offered evidence that the McHenry or Tillis campaigns or the state GOP knew Cambridge had allegedly obtained data on Facebook users by improper means.

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Woodhouse said President Barack Obama's campaign used similar data to target voters in 2012.

Much of the problem with Cambridge stems, The New York Times and other media outlets have reported, from the way it got the data.

The company is accused of using data first obtained under the guise that it would only be used for academic purposes.

Cambridge's website has touted its work for Tillis as a successful example of its work.

The company said it used its “unique data-rich voter file” to build high-tech profiles for all North Carolina voters, and to determine national security was the top issue for the campaign’s target voters. Cambridge wrote that its voter-contact program helped increase turnout by the equivalent of over 15,000 voters. Tillis defeated Hagan by less than 46,000 votes.

Officials in the United Kingdom and the U.S. are reportedly investigating the company's practices. Cambridge Analytica's use of data have become a major privacy scandal for Facebook.

The Associated Press contributed to this report.