A new court filing by special counsel Robert Mueller against former Trump campaign chairman Paul Manafort and his business associate suggest that the Russia probe is a ways from ending.

The filing on Friday ahead of a court appearance scheduled for Manafort and his associate Richard Gates on Monday reveals that Mueller’s investigators have gathered more than 400,000 financial and corporate records and email communications involving the defendants.

“Given the volume of discovery in this case, the government also produced to defendants certain documents that it identified as ‘hot,’” states the filing, which specifies that about 2,000 documents fall in that category.