An assistant to former Trump campaign chairman Paul Manafort granted FBI investigators access to a storage locker that contained evidence Manafort is trying to suppress, according to court testimony on Friday.

FBI special agent Jeff Pfeiffer said during a federal court hearing on Friday that Manafort's assistant, Alex Trusko, told him he had moved numerous documents to the locker at Manafort's request after reporters tipped the FBI off to its existence, Reuters reported. Those documents are reportedly related to numerous charges against Manafort for financial crimes.

Pfeiffer, who searched the locker, revealed the disclosure in a hearing to determine whether evidence in the locker could be used in Manafort's trial, which is set for July.

Manafort's lawyers argued in a hearing last month that his rights against unreasonable searches and seizures were violated during the raid of his home and the storage locker. The lawyers said FBI agents who searched Manafort's storage locker committed an illegal warrantless search, even though the assistant who unlocked the unit was listed on its lease and the FBI agent obtained a warrant to seize the records stored inside the unit.

Manafort, who faces numerous charges for financial crimes related to his lobbying work for pro-Russia political groups in Ukraine, sought unsuccessfully to suppress the evidence in his Washington, D.C., case, arguing that it was improperly handed over to FBI agents.

He is now seeking to suppress evidence in Virginia obtained in a raid of his home. He has pleaded not guilty to charges in Washington and Virginia.

The former top Trump campaign aide is in jail awaiting trial after a D.C. circuit judge ordered him to report to police custody after allegedly violating the terms of his bail agreement.

None of the charges Manafort faces are related to his work for the Trump campaign during the 2016 election, though the charges arose as a result of special counsel Robert Mueller's investigation into potential collusion between Trump's campaign and Russia during that time.