In a federal court filing submitted Monday night, prosecutors for special counsel Robert Mueller revealed that Deputy Attorney General Rod Rosenstein gave Mueller the specific authority to investigate former Trump campaign chair Paul Manafort’s work for Ukrainian officials and his time in the Trump campaign.

The revelation came in the Mueller team’s response to Manafort’s push to dismiss the Washington, D.C. indictment brought against him by arguing that Mueller did not have the power to investigate his work lobbying for Ukrainian officials.

Several months after issuing the public order naming Mueller as special counsel and granting him the authority to investigate ties between the Trump campaign and Russian officials, Rosenstein issued a confidential memo laying out the specifics of Mueller’s probe, according to prosecutors.

The August 2, 2017 memo attached to the Monday night filing grants Mueller the authority to investigate allegations that Manafort “committed a crime or crimes by colluding with Russian government officials with respect to the Russian government’s efforts to interfere with the 2016 election for President of the United States” and “committed a crime or crimes arising out of payments he received from the Ukrainian government before and during the tenure of President Viktor Yanukovych.”

The rest of the details about the investigation laid out in the memo are redacted.

The memo confirms that Mueller is investigating potential collusion by members of the Trump campaign and shows that Mueller planned to investigate Manafort’s work in Ukraine early on.

In their March motion to dismiss the Washington, D.C. indictment against Manafort, his lawyers argued that Rosenstein did not have the power to grant Mueller the authority to investigate any matters that arise from the Russia probe, and that even if Rosenstein did have that power, Manafort’s Ukraine work did not fall within the scope of the Russia investigation.

Mueller’s team argued that Rosenstein did have that power and used the August 2 memo to argue that Mueller had the authority to bring the indictments against Manafort related to his Ukraine work.

In the Washington, D.C. indictment, Manafort faces charges of money laundering, tax evasion, and failure to disclose foreign lobbying. In a separate indictment brought in Virginia, Manafort faces charges of making false statements on tax returns, failing to report foreign bank accounts, and bank fraud. He has pleaded not guilty to both indictments.

Read the Rosenstein memo and the Mueller team’s filing: