Special counsel Robert Mueller's references to "uncharged individuals" in recent court filings that aim to restrict certain evidence are being read by some as an indication more people could be indicted in his sprawling investigation.

Despite rampant speculation that Mueller is close to finalizing his report, the language used in court documents over the past few months offers clues that suggest his probe might ensnare more individuals.

The latest example came last week, when Mueller said sensitive files in the case involving a Russian troll farm identified "uncharged individuals" suspected of engaging in operations "that interfere with lawful U.S. government functions." Mueller's filing sought to keep the evidence restricted from defendants in Russia.

He has also referenced "uncharged individuals" and "ongoing investigations" in the case involving former Trump campaign chairman Paul Manafort.

Legal analysts say those moves indicate federal prosecutors are investigating other subjects linked to the troll farm and Manafort cases who could ultimately be charged if government attorneys obtain evidence of criminal wrongdoing.

"That implies they're still working to indict somebody," said Jack Sharman, who was a special counsel to Congress for the Whitewater investigation during the 1990s. "It also may essentially mean that they want to keep their methods and their approach held close to the vest until they are done with this defendant."

Many are hoping Mueller's report - slated for submission to the Justice Department at the conclusion of the probe - will answer the central question of whether there was any collusion between the Trump campaign and the Kremlin.

But the timing of the report is an open question.

Last February, Mueller charged 13 Russians and three Russian firms with conspiracy to defraud the United States. The Russians allegedly ran the Internet Research Agency, a troll farm that used social media to serve divisive content to U.S. audiences before the 2016 presidential election.

Two Washington-based lawyers are now defending the alleged funder of the troll operation, Concord Management and Consulting, in D.C. federal court. Some court watchers suspect that development is an effort by Russia to obtain sensitive discovery documents from the U.S. government.

Mueller last week objected to the company's request that "sensitive" discovery files be disclosed to its employees for the purpose of trial preparation, and in doing so he revealed that some evidence had already been used in an apparent disinformation campaign to discredit the investigation.

The special counsel also wrote that lifting restrictions on the files - currently subject to a protective order issued by a federal judge in June - would expose information about "uncharged individuals and entities" suspected of engaging in operations "like those activities charged in the indictment."

"Second, information within the sensitive discovery identifies sources, methods, and techniques used to identify the foreign actors behind these interference operations," Mueller wrote.

In a January filing, he also acknowledged an active grand jury probe tied to that case.

"My hunch is that we are going to see more indictments of Russians," said Glenn Kirschner, a former federal prosecutor with the U.S. attorney's office in Washington, D.C.

The special counsel has charged more than two dozen Russians and six Trump associates in connection with the investigation. Mueller has separately indicted a dozen Russian intelligence officers for allegedly hacking the Democratic National Committee and U.S. election infrastructure.

None of the charges have alleged any conspiracy involving both the Trump campaign and the Russian government.

In Manafort's case, Mueller last month asked for permission to redact certain evidence regarding the former Trump aide's alleged lies to federal officials, noting that "the redactions relate to ongoing law enforcement investigations or uncharged individuals, and public disclosure of certain information in the submission could unduly risk harming those efforts."

Manafort pleaded guilty last year to charges stemming from his Ukraine lobbying work and agreed to cooperate in the probe. Mueller later accused him of lying to investigators in breach of his plea deal. Manafort has contested that allegation.

It is possible that the reference to potential targets in Manafort's case falls out of the scope of Mueller's investigation. Manafort is accused of lying about an unknown Justice Department probe run out of another district, and federal prosecutors in Manhattan are said to be investigating other lobbying firms that did work for Manafort, though it is unclear whether Manafort has cooperated with that inquiry.

While Mueller appears to be investigating unnamed potential targets, that does not guarantee future charges.

"I think that oftentimes in a federal criminal investigation, things just get left," Sharman said. "In other words, they simply don't get acted upon because prosecutors decide there is not enough probable cause or there is a strategic reason for not moving things forward."

A spokesman for the special counsel's office declined to comment for this story.

Mueller has faced mounting pressure from the White House to wrap up his investigation, which is also said to be exploring whether Trump has obstructed the probe. The president has maintained his campaign did not collude with Russia and regularly derides the investigation as a "witch hunt."

Last month Mueller unveiled charges against longtime Trump ally Roger Stone for allegedly lying to the House Intelligence Committee about his interactions regarding WikiLeaks, the organization that disseminated troves of Democratic emails before the election, with U.S. intelligence agencies later saying Russia was responsible for obtaining the hacked documents. Stone, who has pleaded not guilty, is also charged with witness tampering and obstructing a congressional investigation.

Days later, acting Attorney General Matthew Whitaker said he believed the Mueller investigation to be "close" to completion. Some have questioned that assertion.

"All outward signs ... suggest that Mueller's investigation is still active and ongoing," said Randall Eliason, a George Washington University law professor. "I think there is reason to believe something else is coming.

"I just don't see any outward signs this investigation is close to wrapping up," added Eliason, a former assistant U.S. attorney in D.C.

The Justice Department said they obtained a significant amount of electronic evidence in searches of Stone's residences, and prosecutors recently requested more time to bring the case to trial. Mueller and the U.S. attorney's office in D.C. are jointly handling Stone's case.

Mueller is also locked in at least two subpoena battles with witnesses, including a mystery foreign government-owned company that is petitioning to take the case to the Supreme Court.

In addition, Mueller has repeatedly sought to delay former Trump campaign aide Richard Gates's sentencing, citing his cooperation with several ongoing investigations.

Furthermore, a federal court in D.C. extended Mueller's grand jury before it expired in January. A grand jury can be extended for up to six months, though there was no timeline given with the extension.

"I don't think we can draw from that alone that there's six months' worth of additional investigating to be done," said Kirschner. "It could be that he's got 30 days' worth."