Paul Manafort plans to file a motion to suppress evidence that was "improperly obtained" via a search warrant or subpoena from special counsel Robert Mueller's office.

A former federal prosecutor said motions to suppress are typically an "uphill battle."

But the motion, if filed, would put the prosecution "on the defensive," waste the government's time, and delay the case, the former prosecutor said.

Paul Manafort plans to file a motion to suppress evidence that was "improperly obtained" by special counsel Robert Mueller's team via a "search warrant, subpoena, or otherwise," according to a new court document filed by his lawyer Kevin Downing on Friday.

Manafort and his longtime business associate Rick Gates were indicted last week on charges related to alleged financial crimes that include money laundering and tax fraud. They turned themselves in to the FBI on Monday and are currently on house arrest.

Mueller said on Thursday that the government would need likely need three weeks to present its case in court against Manafort and Gates.

The FBI conducted a predawn July raid on Manafort's home as part of its ongoing investigation into possible collusion between the Trump campaign and Russia. Agents who came armed with a "no-knock" search warrant found evidence during that raid that Manafort had been withholding from them, according to the indictment.

A motion to suppress is "fairly common" in complex white collar criminal cases like the one Mueller has brought against Manafort and Gates, said former federal prosecutor Renato Mariotti. But it will likely face a steep uphill battle.

"The judge made an independent finding of probable cause," Mariotti said. "So the issue Manafort's lawyers raise will be: did law enforcement mislead the judge or make material ommissions from their search warrant affidavit? It seems like Mueller's team would have been very careful about crafting that search warrant, so that will be an uphill battle."

Mariotti noted that the motion to suppress could have some benefits for Manafort, even if it is not approved.

"It puts the prosecution on the defensive, wastes the government's time, and delays the prosecution," Mariotti said. "But I think the chances of success are extremely low."

The Manafort/Gates indictment was unsealed Monday morning, and it contains 12 counts: conspiracy against the United States, conspiracy to launder money, unregistered agent of a foreign principal, false and misleading FARA statements, false statements, and seven counts of failure to file reports of foreign bank and financial accounts.

The indictments against Manafort and Gates are the first since James Comey launched the investigation over a year ago. Mueller took over the investigation after Comey was fired as FBI director in May.

Read Manafort's response below: