Rick Gates, the former campaign aide to Donald Trump, is cooperating with Special Counsel Robert Mueller’s probe into whether individuals from the Middle East worked with the Trump campaign to influence the election, according to two individuals with first-hand knowledge of the investigation.

Gates has answered questions specifically about Psy Group, an Israeli firm that ex-employees say drew up social media manipulation plans to help the Trump campaign, according to sources familiar with the questions. Mueller’s team also asked Gates about interactions with Psy Group’s owner, Joel Zamel, and Lebanese-American businessman George Nader, who worked as an emissary for Saudi Arabia and the United Arab Emirates, the sources said.

On Tuesday, Mueller’s team said that Gates was cooperating with “several ongoing investigations” in asking a federal judge to delay his sentencing for financial crimes he pleaded guilty to committing with former Trump campaign chairman Paul Manafort. One of the ongoing investigations is into possible Middle Eastern election influence, three people with knowledge of the probe told The Daily Beast.

A lawyer for Gates did not respond to requests for comment. Zamel’s lawyer declined to comment for this story, but previously said in other reports that Zamel cooperated with the special counsel’s office. The special counsel’s office declined to comment.

Gates requested proposals in 2016 from Psy Group that would help Trump in his campaign for president, The New York Times reported last year. Those proposals included social media manipulation tactics such as creating fake avatars to engage voters and Republican campaign delegates. Gates reportedly spoke about the proposals with George Birnbaum, a Republican consultant with connections in Israel. Former Psy Group employees who spoke with The Daily Beast said they only interacted with Birnbaum, whom they were introduced to by an intermediary, and did not have contact with Gates.

Mueller asked Gates whether the Trump campaign approached Psy Group, or whether Psy Group, through intermediaries like Birnbaum, approached representatives of the Trump team, according to two sources familiar with Gates’ cooperation.

Former employees of Psy Group told the Times they asked Washington-based law firm Covington and Burling if the plan violated laws that regulate foreign participation in American elections. Employees told The Daily Beast that the law firm said it was legal to proceed with the plan if the firm took certain steps to involve U.S. individuals. Covington and Burling did not comment for this story.

Psy Group employees told The Daily Beast they have been interviewed by the FBI, which asked about two Republicans other than Gates who had made overtures from Trump world to Psy Group in 2016. Both represented themselves as members of Trump’s inner circle and were introduced to Psy Group by “brokers,” including Birnbaum, the former employees said. Former employees said they could not reveal the names, citing non-disclosure agreements. (Psy Group is in the process of liquidation.)

It is unclear if Zamel or Psy Group ever carried out the campaign for Trump.

At the same time, Zamel had his own discussions with Trump associates. The special counsel’s office has examined whether Zamel’s interactions with the Trump team, and his conversations about a plan to help Trump win the election, overlapped or coincided with conversations Psy Group employees had with Birnbaum and Gates.

Zamel told employees he used Psy Group material in conversations with Trump associates, the employees said.  

“Joel is a very secretive guy, he holds all his cards very close to the chest,” one former employee said. “It’s very possible he was running some sort of side operation that used Psy resources but didn’t include the staff.”

Mueller’s team is still actively looking at Zamel’s interactions with the Trump team beyond Psy Group, according to sources familiar with Gates’ cooperation.

After the election,  Zamel helped craft a plan a plan for regime change in Iran. The Daily Beast was the first to report the meeting, which included Zamel, Nader, incoming national security advisor Michael Flynn, and a Saudi general, Ahmed al-Assiri. During this time, Nader was also promoting a plan for the U.S. to carry out economic sabotage against Tehran. The meeting appears to be part of Saudi and Emirati efforts to lobby the incoming Trump administration against Qatar and Iran, their top regional competitors.

The special counsel’s office is also probing a payment made from Zamel to Nader for $2 million after the election. Mueller has questioned multiple witnesses, including Gates, about that payment, according to three sources with knowledge of his team’s questioning.

Mueller’s team is also examining whether foreigners illegally donated to Trump’s inaugural committee via American intermediaries leading up to Trump taking office. One matter of interest is a breakfast meeting that took place at the Trump International Hotel in Washington three days before the presidential inauguration. That event included Flynn, then-House intelligence committee chairman Rep. Devin Nunes (R-CA), and GOP mega donors. Dozens of foreign officials, including those from the UAE, Saudi Arabia, Israel, and Qatar, were invited to the event.