More information has come out highlighting possible troubling connections of Republican presidential nominee Donald Trump to the Vladimir Putin regime in Russia.

The New York Post reported that, according to sources, former campaign chairman Paul Manafort and ex-”core” aide Rick Gates have financial ties to a biometric security company that lobbied the Putin administration on behalf of technology that would help it spy on its citizens.

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Manafort was a major early investor for EyeLock and owned as much as 10 percent in the company, according to the Post, while Gates served as an independent contractor hired to build business for it in Middle Eastern countries like Saudi Arabia and the United Arab Emirates.

EyeLock uses iris-scanning technology to identify individuals, according to its website. The company had a failed bid to put machines in the Moscow subway to scan as many as 50 people a minute to find matches with those on watch lists.

This isn’t the first time that Manafort and Gates have been reported as having pro-Putin ties. In August, Manafort was pressured into resigning after news stories indicated that he had lobbied on behalf of a Ukrainian president sympathetic to Putin, Viktor Yanukovich. Gates resigned shortly after that.

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“It raises a lot of questions about national security and what should have been publicly disclosed to get a better handle on ties between the Trump campaign and the Russian government,” a White House official told the New York Post about Manafort’s lobbying ties.

Trump’s potential ties to the Putin regime have been a significant issue in this presidential election. Trump has taken fire for praising Putin, most notably in September when he said, “He’s been a leader far more than our president has been a leader.”

In July, when the hacking of the Democratic National Committee's emails made headlines, Trump seemed to encourage Russia to continue sabotaging the party of his opponent: “Russia, if you’re listening, I hope you’re able to find the 30,000 emails that are missing.” Trump delegates also fought to insert pro-Russia planks into the Republican Party platform at its national convention in July.