Special counsel Robert S. Mueller III fired his opening salvo this week, unsealing charges against three former Trump campaign aides thought to have engaged in a medley of wrongdoing.

The cases he revealed, legal analysts say, indicate he is pursuing an extensive probe that will explore both personal wrongdoing of those connected with Trump, and possible efforts campaign officials took to work with Russia to influence the 2016 election.

Collusion — the word Trump often uses to describe Mueller's case, even as he asserts such a thing never happened — is not itself a crime, and Mueller's team will likely have to sort through unseemly political dealings to determine if a law was broken, legal analysts say. In his first public charges, though, Mueller offered a hint of the direction he might take.

Former campaign foreign policy adviser George Papadopoulos, for example, pleaded guilty to making a false statement to FBI investigators who asked about his contacts with foreigners claiming to have high-level Russian connections.

Of particular note, he falsely described his interactions with a London-based professor claiming to have connections to high-level Russian officials who purportedly had "dirt" on Hillary Clinton in the form of "thousands of emails."

Papadopoulos claimed his interactions with the professor — thought to be Joseph Mifsud, the director of the London Academy of Diplomacy — occurred before he joined the campaign and did not amount to much. In fact, the professor told him about the emails in April 2016 — after his role on the campaign was made public — and the two were involved in extensive discussions about a possible meeting between Trump campaign and Russian officials, according to Papadopoulos' plea agreement.

The conversation about emails is possibly a critical piece of evidence, legal analysts said. That is because one charge that investigators might try to substantiate against those higher in the Trump campaign is a conspiracy to violate the Computer Fraud and Abuse Act.

If Mueller can find evidence that members of Trump's team conspired in Russia's hacking effort — by directing it or aiding in some other way — they might face criminal charges, legal analysts said. Papadopoulos' plea says that he discussed some of his efforts to broker a meeting with Russians with other, more senior Trump campaign officials — though some seemed to treat him warily.

"There's a significant difference between the Russians having dirt and offering that dirt, and someone asking the Russians to commit an illegal act to obtain that dirt," said Jacob Frenkel, a white collar attorney at Dickinson Wright who previously worked in the now-defunct Office of Independent Counsel. "The latter likely would be prosecutable, and probably as a conspiracy to commit a computer crime, or as a computer crime."

Papadopoulos' conversation about "emails of Clinton" took place a month after Clinton campaign Chairman John Podesta's email account was hacked, and occurred well before WikiLeaks had released his messages. Also, it was not until June 2016 that The Washington Post reported that the Democratic National Committee had been breached.

But at that time, it was well known that Clinton had deleted tens of thousands of emails she deemed personal from her private server. Those messages were of great interest to Republicans who believed they might show something nefarious.

It was unclear to what emails the Russian professor was referring, or even if he truly had access to any messages damaging to Clinton. Jonathan Biran, a former federal prosecutor now in private practice at Biran Kelly, said Mueller's team is likely asking, "What did people within the campaign know about how those emails had been obtained, and whether they had reason to believe they had been obtained illegally?"

Aaron Zelinsky, a lawyer in the special counsel's office, said at Papadopoulos' plea hearing, which was held in secret earlier this month, that the foreign policy adviser's case was a "small part" of a "large scale ongoing investigation." Though Papadopoulos was first arrested in July, the court kept his case sealed for months after prosecutors asserted that making it public would "significantly undermine his ability to serve as a proactive cooperator."

Former Trump campaign chairman Paul Manafort and Rick Gates, his longtime business partner, were charged in a separate, 12-count indictment in connection with their work advising a Russia-friendly political party in Ukraine. While their charges do not directly relate to their roles on the Trump campaign, legal analysts said the case could offer a preview of how Mueller plans to proceed.

Among many other counts, including conspiracy to launder money and failing to file reports of foreign bank accounts, Manafort and Gates were charged with carrying out a conspiracy against the United States. Specifically, the special counsel alleged they worked to defraud the Justice and Treasury departments as they tried to hide their income and lobbying work for Ukrainian interests.

Mueller could be working to convince Manafort and Gates to cooperate, and he could also be trying to send a message to others in Trump's orbit that he will leave no stone unturned, and those that deceive investigators will be charged, legal analysts said.

But Mueller also could be signaling a charge he could pursue in connection with the coordination case - a conspiracy to defraud the United States, by coordinating with Russia.

"Collusion is not a crime, but basically the criminal equivalent is conspiracy," said former federal prosecutor Randall Eliason. "You could have a conspiracy to defraud the U.S. by interfering with our election."

Mueller must also separate efforts that might seem seedy from those that would be illegal.

An opposition research firm funded by Hillary Clinton's campaign and the DNC tapped a former British spy to dig into Trump's personal and business dealings, and the former spy purportedly solicited information from Russian government officials. That work might similarly be viewed as an unsavory effort to engage with foreign interests to win an election, but it would not necessarily be illegal if there was no conspiracy to defraud anyone, legal analysts said.

"There could be something out there that stinks to high heaven," Frenkel said, "but it doesn't make it a violation of law."

Devlin Barrett contributed to this report.