Mike Flynn's sentencing memo could spell doom for Jared Kushner -- who took part in some of his sketchiest schemes

Michael Flynn's sentencing memo could spell deep trouble for Jared Kushner, the son-in-law to President Donald Trump and a senior White House adviser.

The heavily redacted court document shows Flynn, who was a constant presence on the 2016 campaign trail with Trump and during his 24-day tenure as national security adviser, has been interviewed 19 times by special counsel Robert Mueller and investigators in two other cases.

The memo offered few clues about the nature of Flynn's testimony, but Mueller's team noted the retired U.S. Army general had offered "substantial assistance" to investigators.

That should worry Kushner, who took part in some of the episodes that Flynn later pleaded guilty to lying about.

"The meat of what should worry Team Trump is in Mueller’s disclosure that Flynn has provided firsthand information about interactions between the transition team and Russian government officials – including, as was already known, several conversations with (then-Russian ambassador Sergey) Kislyak in December 2016," wrote Trump biographer Tim O'Brien for Bloomberg Opinion. "Those included a discussion about lifting economic sanctions the Obama administration had imposed on Russia and about a separate matter involving a United Nations resolution on Israel."

Flynn pleaded guilty a year ago for lying to federal agents Jan. 24, 2017, about those contacts, and Mueller's memo shows his investigators are still interested in the contacts he tried to keep secret.

The FBI investigated Kushner's own contacts with Kislyak until the White House adviser reportedly urged Trump to fire its director, James Comey, in spring 2017 -- and which Mueller, who was named special counsel in response, is now investigating as possible obstruction of justice.

Both Comey and now Mueller have focused on possible favor-trading between the Trump campaign and the Kremlin, and the cash-strapped Kushner joined Flynn on Dec. 1, 2016, for a Trump Tower meeting with Kislyak to arrange a subsequent meeting with a Russian banker.

"FBI investigators are examining whether Russians suggested to Kushner or other Trump aides that relaxing economic sanctions would allow Russian banks to offer financing to people with ties to Trump," a U.S. law enforcement official told Reuters when the meeting was first reported in May 2017.

The White House has insisted that the undisclosed Dec. 13, 2016, meeting with Sergei Gorkov -- head of the state-owned Vnesheconombank and a trained intelligence officer -- was part of Kushner's diplomatic duties.

Kushner and Flynn also did not disclose their meetings with Kislyak during the transition period to discuss setting up a back channel between Trump and Russian President Vladimir Putin that would have bypassed diplomats and intelligence agencies.

"It is unclear who first proposed the communications channel, but the people familiar with the meeting said the idea was to have Mr. Flynn speak directly with a senior military official in Moscow to discuss Syria and other security issues," reported the New York Times, which first revealed Kushner's role in the scheme.

Flynn asked Kislyak to delay a UN Security Council resolution related to Israel on Dec. 22, 2016 -- before Trump was sworn in -- and later lied to the FBI about it.

Court documents later revealed an unnamed "very senior member of the Presidential Transition Team" directed Flynn to contact Kislyak about that UN vote -- which Bloomberg News later reported was Kushner.

Mueller's memo doesn't discuss Kushner's role in these events, but that doesn't mean he's off the hook.

"The absence of greater detail might cause Kushner to worry," O'Brien wrote. "If Flynn offered federal authorities a different version of events than Kushner – and Flynn’s version is buttressed by documentation or federal electronic surveillance of the former general – then the president’s son-in-law may have to start scrambling."