New documents reveal that special counsel Robert Mueller may be trying to use his investigation of Donald Trump’s former campaign chairman, Paul Manafort, to probe deeper into Trump’s 2016 presidential campaign.

Mueller has been seeking information from Manafort about foreign political donations and the meeting between top Trump campaign officials and Russian operatives in Trump Tower. The new details were included in a heavily redacted search warrant application in a motion by Manafort’s lawyer to try to suppress evidence taken in the July 2017 raid of Manafort’s Virginia home.

The warrant is further evidence that investigators are not limiting their case against Manafort to payments he received as part of his work for the pro-Russian Party of Regions in Ukraine and are searching for other threads that go directly to the Trump campaign.

A federal agent specializing in computers and data recovery wrote that they were searching for records showing work Manafort and his longtime lieutenant, Rick Gates, did on behalf of foreign governments, officials and others. Agents working for Mueller also sought documents regarding the attendees of the June 2016 Trump Tower meeting, as well as Aras Agalarov, a Russian real-estate magnate close to Russian President Vladimir Putin, and his son, Russian pop singer Emin Agalarov.

Manafort was one of three top Trump advisers who met with Russians trying to end economic sanctions against Russian oligarchs. Trump’s eldest son, Donald Trump Jr., and his son-and-law and senior adviser, Jared Kushner, also attended the meeting in June 2016 with representatives of the Agalarovs. Trump Jr. took the meeting despite it being described in emails as being part of a Russian government effort to aid his father’s Republican campaign.

A spokesman for the special counsel’s office did not immediately return a request for comment. A Manafort spokesman declined to comment Tuesday, noting the gag order in place.

Manafort is alleged to have hidden payments from former Ukrainian Prime Minister Viktor Yanukovych and his political party. Gates agreed in February to plead guilty as part of a deal that has him now helping Mueller’s team.

Manafort’s legal team has been fighting to dismiss the criminal case against Manafort and has also filed a lawsuit as part of an attempt to block any future charges against him stemming from his work in Ukraine.

(AP)