Special Counsel Robert Mueller’s federal grand jury was granted a six-month extension to pursue criminal activity relating to Russian interference during the 2016 presidential election, after its initial 18-month term limit was set to expire over the weekend.

Mueller was given the authority by the Justice Department to prosecute individuals as he sees fit as long as they fall within his specific commissioned authority – and with the permission of a grand jury, secret group of 23 individuals in D.C. who approve the criminal indictments. The extension serves as possibly the surest indication that the special counsel’s work is far from wrapping up and that there may be more indictments to come.

The grand jury began meeting in July of 2017 and are dedicated to the Mueller probe. Since it began, they have heard from dozens of witness testimonies and oversaw the approval on the indictments of disgraced Trump campaign chairman Paul Manafort, his deputy Rick Gates,  Russian businessman Konstantin Kilimnik, 12 Russian military officers, 13 Russians, who allegedly in an attempt to sway voters manipulated social media during the 2016 campaigns.

Manafort and Gates have since plead guilty and accepted a reduced set of charges in exchange for their cooperation. Meanwhile, one Russian company, Concord Management & Catering, has pleaded not guilty and the others have yet to appear in U.S. courts.

There have been several signs in recent months that the Mueller probe would continue on in its investigation. Associates of Roger Stone, an adviser to the president, have recently received grand jury subpoenas with Stone himself stating publicly that he’s expecting an eventual indictment as well.

Federal rules state that the courts are able to extend a grand jury’s term for up to six months as long as it remains “in the public interest.”

The extension was granted by Chief Judge Beryl Howell of the D.C. District Court who oversees the Mueller grand jury but does not sit in on its private sessions.