(CNN) Paul Manafort's lawyers are so concerned he might not have a fair trial that they could ask for a location change before a Northern Virginia jury considers the lobbyist-turned-Trump-campaign-chairman's alleged tax- and banking-related crimes at the end of July.

The possibility came up during a discussion in court Friday about whether Justice Department and FBI officials had leaked grand jury or other investigative secrets to the media. If they had, and if information in the leaks was untrue, that could unfairly bias members of a jury, Manafort's lawyers have said.

Manafort's attorneys didn't say Friday whether they would indeed ask to move the trial, though federal Judge T.S. Ellis strongly suggested they do if they wanted to keep pressing prosecutors about leaks. He said he wouldn't dismiss the case because of the leaks accusation and that he might consider sanctioning government investigators and prosecutors. But before Ellis would even get to that, defense lawyers must try to convince him there's reason to believe leaks happened.

"I'm not going to have a hearing on the leaks (before the trial). You used the word 'satiated' (about media coverage)," Ellis told Manafort lawyer Kevin Downing. "Prove it."

Manafort, who has maintained his innocence, is set to go on trial July 25 in the Alexandria courthouse.

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