A federal judge ruled Tuesday that special counsel Robert Mueller must identify the unnamed individuals in his recent superseding indictment of former Trump campaign chairman Paul Manafort.

Mueller last week indicted Manafort and his former aide, Konstantin Kilimnik, on a series of charges related to lobbying work on behalf of Ukraine.

The indictment accused Manafort and Kilimnik of obstructing justice by attempting to tamper with witnesses in the investigation.

Judge Amy Berman Jackson ordered Mueller to turn over the names of several individuals and organizations, including European politicians and other Manafort contacts, to Manafort’s attorneys, according to court documents and reports by Politico.

{mosads}The New York Times reported last week that two veteran journalists told Mueller that Manafort attempted to contact them and tried to shape their testimony. Three Times sources identified the journalists as Alan Friedman and Eckart Sager. Mueller’s indictment did not name the witnesses that Manafort and Kilimnik allegedly contacted.

Jackson’s ruling comes in response to a motion from Manafort’s team seeking more information on the superseding indictment.

Jackson wrote that Mueller turning over the information will help Manafort prepare for a “complex” trial, which is expected in September.

“[The] defendant is obliged to prepare for a complex trial with a voluminous record within a relatively short period of time, and he should not have to be surprised at a later point by the addition of a new name or allegation,” she wrote.

Manafort has also been indicted on multiple charges related to financial crimes and is expected to go to trial next month. He has pleaded not guilty to all charges.