Robert Mueller's report is expected to be made public on Thursday, and while parts of it are expected to remain under wraps, some elements of the probe are known to the public – including its cost.

From the day the special counsel was appointed and throughout his 22-month investigation, his office has released statements of expenditures every few months detailing its spendings.

Three such statements are currently available, with a fourth one likely coming soon.

Based on the published statements, plus an estimate of what is to come in the fourth statement, it appears likely that the Mueller investigation itself will have cost around $17m.

The special counsel’s office also reported Department of Justice spending that supported its activities, stating that it wasn’t legally required to do so and that those expenditures would have occurred regardless of whether or not the special counsel’s office was conducting an investigation. If those additional expenditures are taken into account, the final estimate for the cost of the Mueller investigation reaches around $31m.

Mueller investigation: The key figures Show all 12 1 /12 Mueller investigation: The key figures Mueller investigation: The key figures Robert Mueller is the special counsel overseeing the investigation into Russia's meddling in the 2016 election, and potential obstruction of justice by the president. Mr Mueller has a pristine reputation in Washington, where he was previously in charge of the FBI. Throughout his investigation, he and his team have been notoriously tight lipped about what they know and where their investigation has led. REUTERS Mueller investigation: The key figures Former FBI director James Comey was the catalyst that led to the appointment of special counsel Robert Mueller. Mr Comey was fired by the president after Mr Trump reportedly asked him to drop his own Russia investigation. Mr Trump has long maintained that the investigation is a "witch hunt". AFP/Getty Images Mueller investigation: The key figures Deputy attorney general Rod Rosenstein had authority over the special counsel investigation for much of the two years it has been active. Mr Rosenstein found himself with that responsibility after then-attorney general Jeff Sessions recused himself from that oversight. AP Mueller investigation: The key figures Attorney general Jeff Sessions's decision to recuse himself from oversight of the special counsel investigation may have cost him his job in the end. Mr Sessions resigned last year, after weathering a contentious relationship with Donald Trump who vocally criticised his attorney general for taking a step back. Mr Sessions recused himself from the oversight citing longstanding Justice Department rules to not be involved in investigations overseeing campaigns that officials were apart of. AP Mueller investigation: The key figures Attorney General William Barr is currently responsible for oversight of the special counsel investigation. Mr Barr's office will be the first to receive the Mueller report when it is finished. His office will then determine what portion or version of that report should be delivered to Congress, and also made public. EPA Mueller investigation: The key figures Michal Cohn is the president's former personal lawyer, who has been helping the special counsel investigation as a part of a plea deal over financial crimes, and campaign finance crimes, he has pleaded guilty to. Among those crimes, Cohen admitted to facilitating $130,000 in hush money payments to adult film actress Stormy Daniels during the 2016 campaign. Cohen has said he did so at the direction of Mr Trump. Cohen has also admitted that he maintained contacts with Russian officials about a potential Trump real estate project in Moscow for months longer than Mr Trump and others admitted. The talks continued well into 2016 during the campaign, he has said. AP Mueller investigation: The key figures Stormy Daniels has alleged that she had an affair with Donald Trump in 2006, soon after Melania Trump gave birth to Baron Trump. The accusation is of particular importance as a result of the $130,000 hush money payment she received to keep quiet about the affair during the 2016 campaign. AP Mueller investigation: The key figures Paul Manafort was Donald Trump's former campaign chairman. Manafort was charged alongside Rick Gates for a slew of financial crimes, and was convicted on several counts in a Virginia court. He then pleaded guilty to separate charges filed in a Washington court. Manafort has been sentenced to just 7.5 years in prison for his crimes — in spite of recommendations from the special counsel's office for a much harsher sentence. AP Mueller investigation: The key figures George Papadopoulos was one of the first individuals associated with the Trump campaign to be charged by the Mueller probe. He ultimately received a 14 day prison sentence for lying to investigators about contacts he had with Russian officials. AP Mueller investigation: The key figures Roger Stone is a well known political fixer and operative, who has made a name for himself for some dirty tactics. He has been charged by the Mueller probe earlier this year, and he has been said to have had prior knowledge that WikiLeaks planned on publishing stolen emails from the Hillary Clinton campaign in 2016. Getty Images Mueller investigation: The key figures Rick Gates was charged alongside former Trump campaign chairman Paul Manafort for a range of crimes. Gates, who worked alongside Manafort for a pro-Russia Ukrainian political party. The two were charged with conspiracy and financial crimes. Gates pleaded guilty. AP Mueller investigation: The key figures Former national security adviser Michael Flynn was one of the first casualties of the Russia scandal, and was forced out of his position in the White House weeks after Donald Trump took office. Flynn pleaded guilty in 2017 to "willfully" making fraudulent statements about contacts he had with Russian officials including former Russian ambassador to the US Sergey Kislyak. Flynn then lied to Vice President Mike Pence about that contact. REUTERS

Mr Mueller’s office filed its first expense report for the period of 17 May, 2017 (when Mr Mueller was first appointed as special counsel) to 30 September, 2017.

The special counsel’s expenses for that period came to roughly $3.2m, with an additional $3.5m in DOJ expenditures, amounting to $6.7m in total.

The second expense report covers the period from 1 October, 2017 to 31 March, 2018 and includes costs of $4.5m with an additional $5.5 in DOJ expenditures, meaning about $10m total.

The third expense report is dated 1 April, 2018 to 30 September, 2018, and states that Mr Mueller’s office spent $4.5m, with approximately $4m of additional DOJ spendings, for a total of about $8.5m.

This means that the special counsel’s office has reported a total of about $12.2m in spendings without the DOJ expenditures, and $25.2m if DOJ expenditures are taken into account.

While the fourth and final expense report has yet to be published, it is possible to make an estimate based on the three reports that have already been filed.

The fourth report will cover a period of six months (between September 2018 and March 2019). Based on the previous three reports, will likely feature expenses of between $4m and $5m for the special counsel’s office, meaning a conservative total estimate of $16m to $17m. If the DOJ components are included at a projection of approximately $5m, the previous total of $25.2 jumps to about $30m or $31m.

This is below figures previously touted by Donald Trump, who in a November 2018 tweet claimed the probe had cost $40m.

Mr Mueller’s report found no evidence that Mr Trump’s campaign ”conspired or coordinated” with Russian officials to influence the 2016 election, according to a letter authored by Attorney General William Barr.

The special counsel initially submitted his findings to Mr Barr Barr, who in March released a four-page summary. Mr Mueller said in a passage from the report quoted by Mr Barr that there was no evidence that Trump “was involved in an underlying crime related to Russian election interference”, but he reached no conclusion on whether Mr Trump obstructed justice.

Mr Mueller neither accused Mr Trump of obstruction of justice in trying to impede the investigation nor exonerated him of obstruction, according to Mr Barr’s summary.

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The Justice Department expects to make a redacted version of Mr Mueller's report on the Russia investigation public on Thursday morning.

The redacted report would be sent to Congress and also made available to the public, Justice Department spokeswoman Kerri Kupec said on Monday.