One of the White House advisers closest to President Donald Trump is beefing up his legal representation for the federal investigation into Russia’s interference in the 2016 election: Trump’s son-in-law, Jared Kushner.

In addition to his personal attorney, Jamie Gorelick, Kushner has retained veteran criminal defense lawyer Abbe Lowell to help handle his response to special counsel Robert Mueller’s sprawling probe, according to reports that surfaced Monday. Lowell has been involved in some of the biggest scandals to hit D.C. in recent years, representing disgraced Republican lobbyist Jack Abramoff and shepherding Democratic vice-presidential nominee John Edwards through a campaign finance case that was ultimately dropped by the Justice Department.

Kushner “engaged Abbe Lowell to advise him and then decided to add Mr. Lowell to the team representing him in the various inquiries into the Russia matter,” Gorelick confirmed to Politico.

He is one of at least 10 White House officials and former aides who have retained attorneys or plan to retain attorneys to field the federal investigation, according to the Wall Street Journal.

Along with reports that Trump himself is under investigation for possibly attempting to obstruct the probe, investigators’ interest in Kushner shows how far the Russia probe has reached into the President’s inner circle.

While current and former U.S. officials with knowledge of the investigation have told various news outlets that Kushner is not a target and his lawyers say he is cooperating fully with Mueller’s office, his meetings with Russian officials and businessmen and his personal finances are all under scrutiny, according to reports in the Washington Post and New York Times.

Here’s what we know about Kushner that has caught federal agents’ attention.

Meetings with Russia’s ambassador and discussion of a secret communications channel

Kushner first came under FBI scrutiny last year as agents began digging into former national security adviser Michael Flynn’s ties to Russian officials, according to Reuters. A current U.S. law enforcement official told the publication that Kushner was one of the American names unmasked in intelligence reports detailing communications between Flynn and Russian officials. This prompted further scrutiny into Kushner’s own dealings with Russia’s Ambassador to the U.S., Sergei Kislyak.

Those dealings included a remarkable December discussion about setting up a secure, secret communications channel between the Trump transition team and Moscow, according to a Washington Post bombshell report. Kushner reportedly proposed establishing this direct line of contact, and communications intercepted by the U.S. showed that Kislyak told his superiors he was surprised by Kushner’s suggestion to use communications equipment in stateside Russian diplomatic facilities to carry it out.

The White House did not dispute reports about this Trump Tower meeting, which Flynn, then the national security adviser-designate, attended. Some members of the administration publicly said they saw no issue with a transition team establishing a secret line of communication with a sitting foreign government, even praising the move.

This was hardly Kushner’s only conversation with Kislyak. Reuters also reported that Kushner had failed to disclose at least three additional contacts with the Russian ambassador, including two phone calls between April and November 2016. All of their communications are now under federal scrutiny, according to that report.

In a statement to Reuters, Gorelick said Kushner did not remember those phone calls.

“Mr Kushner participated in thousands of calls in this time period,” she said. “He has no recollection of the calls as described. We have asked (Reuters) for the dates of such alleged calls so we may look into it and respond, but we have not received such information.”

Meeting with head of a sanctioned Russian bank

Investigators are looking into the backstory of another meeting Kushner held in December, this time with the head of a Russian state-owned bank with deep connections to Russia’s intelligence agency.

Why Kushner met with Sergey Gorkov, CEO of Vnesheconombank, and what they discussed is a line of inquiry for federal investigators, according to the The New York Times. Current and former U.S. officials told the newspaper the conversation may have been part of Kushner’s effort to contact the Kremlin without the Obama administration’s knowledge, and that investigators want to know if they discussed lifting sanctions that Obama’s team imposed on Russian companies, including Vnesheconombank, in retaliation for Moscow’s annexation of Crimea.

The White House has said that Kushner met with Gorkov in his capacity as a transition official, while the bank said Gorkov met with Kushner in his private capacity as head of his family’s real estate company.

Both this meeting with Gorkov and the “backchannel” discussion with Kislyak were initially left off of Kushner’s security clearance application, an omission Gorelick has said was in error and subsequently corrected.

The data operation credited with Trump’s victory

The Trump campaign’s robust data analytics operation, which Kushner oversaw, is currently under federal scrutiny, CNN reported. Investigators want to know if the San Antonio, Texas-based data team wittingly or unwittingly funneled information to Russian operatives. The U.S. intelligence community says Russian hackers strategically targeted certain states and demographics with social media bots and “fake news” sites pushing pro-Trump stories.

CNN reported that Kushner helped the campaign make use of data targeting to reach voters in states like Michigan and Wisconsin, who ultimately ended up securing Trump’s electoral victory.

Kushner’s personal finances and some of his business dealings

Kushner’s business dealings and personal finances are the latest area of inquiry that U.S. officials have divulged are part of Mueller’s probe, the Washington Post reported.

Investigators want to know if Kushner was trying to secure funding for his family real estate company’s flagship Manhattan office building, the troubled 666 Fifth Avenue, when he met with Gorkov in December, U.S. officials told the Post. At the time of the meeting, Kushner Companies was known to be seeking financing for the building, which has lost money since Kushner purchased it for an astonishing $1.8 billion in 2007.

The Post did not name other specific real estate or business dealings tied to Kushner that were under investigation. Gorelick said it was within the special counsel’s purview to look into the Russia-linked business dealings involving any Trump associate.

“It would be standard practice for the Special Counsel to examine financial records to look for anything related to Russia,” Gorelick told the Post. “Mr. Kushner previously volunteered to share with Congress what he knows about Russia-related matters. He will do the same if he is contacted in connection with any other inquiry.”