Special counsel Robert Mueller’s prosecutors have told defense lawyers in recent weeks that they are “tying up loose ends” in their investigation, providing the clearest clues yet that the long-running probe into Russia’s interference in the 2016 election may be coming to its climax, potentially in the next few weeks, according to multiple sources close to the matter.

The new information about the state of Mueller’s investigation comes during a pivotal week when the special counsel’s prosecutors are planning to file memos about three of their most high profile defendants — former Trump national security adviser Michael Flynn, former Trump campaign chairman Paul Manafort and former Trump personal lawyer Michael Cohen.

A Flynn sentencing memo is due Tuesday, and memos about Manafort and Cohen are slated for Friday. All three documents are expected to yield significant new details on what cooperation the three of them provided to the Russia investigation.