After 18 months, special counsel Robert Mueller’s investigation has made public a lot of facts about Russian meddling in the 2016 election and the actions of some key figures in the Trump Administration.

But it’s also raised new questions which have yet to be answered.

The investigation led by the former FBI director has already resulted in more than 100 criminal counts against 33 people and three companies, according to a count by the New York Times.

These include 12 Russian intelligence officers; Donald Trump’s former campaign chair, Paul Manafort; Manafort’s aide, Rick Gates; Trump’s former national security adviser, Michael Flynn; and a foreign policy campaign adviser, George Papadopoulos.

Former Trump lawyer Michael Cohen, who pleaded guilty in August to charges of tax evasion, bank fraud, campaign finance violations which were not filed by the special counsel but stemmed from its investigation, has also pleaded guilty of lying to Congress in a deal handled by Mueller’s team.

Here are some of the unanswered questions the Mueller investigation has raised so far.

How did Donald Trump respond to the Mueller team’s questions?

After long discussions about a potential sit-down interview with President Trump, Mueller’s team settled for written answers to some questions related to Russian interference in the elections. (They have not ruled out a sit-down interview at some point, however.)

Mueller’s team reportedly had at least four dozen questions on subjects such as Trump’s firing of FBI Director James Comey, a potential real estate deal in Moscow and contacts he had with longtime confidant Roger Stone, among other things.

Trump told reporters two weeks ago that he had spent time with his lawyers but had answered the questions himself.

“My lawyers don’t write answers, I write answers,” Trump said.

Trumps lawyers have repeatedly argued that the president should not be questioned about obstruction of justice, with former New York City Mayor Rudy Giuliani arguing the questions would intrude on the president’s constitutional authority.

“It has been our position from the outset that much of what has been asked raised serious constitutional issues and was beyond the scope of a legitimate inquiry,” Giuliani said in a statement, according to NBC News. “This remains our position today. The President has nonetheless provided unprecedented cooperation.”

After Cohen admitted to lying to Congress about the Moscow real estate deal in a Manhattan courtroom Thursday, Trump’s lawyers told the Times that the president gave similar answers in his written responses as Cohen did in his updated plea agreement.

But a full list of Mueller’s questions — as well as how Trump answered them — is not yet public.

What contacts did WikiLeaks have with Trump confidants?

The Mueller investigation is working to determine whether the Trump campaign knew that WikiLeaks was planning to release emails stolen by Russian hackers from Democratic Party leaders.

The Guardian reported on Tuesday that former Trump campaign manager Paul Manafort met with WikiLeaks founder Julian Assange secretly in 2013, 2015 and 2016 at the Ecuadorian embassy in London. Both Manafort and Assange have denied meeting, and WikiLeaks also tweeted a denial of the meeting. The Guardian later weakened some of the claims in its story.

Another figure who may have tipped the Trump campaign off about the emails is Roger Stone, an informal Trump campaign adviser who has previously admitted that he corresponded with “Guccifer 2.0,” an online alias used by at least one Russian intelligence operative who claimed to have hacked the Democratic leaders.

While Stone has denied having contact with Assange, a draft of a plea deal Mueller offered to conspiracy theorist and writer Jerome Corsi says that an unnamed individual, who the Post identifies as Stone, asked Corsi to reach out to Assange days after the emails were released.

The Washington Post reported yesterday that Trump had conducted a “series” of phone calls with Stone over the course of his campaign. In August of 2016, Stone tweeted enigmatically about Clinton campaign chairman John Podesta, whose hacked emails were later released on WikiLeaks.

“Trust me, it will soon the Podesta’s time in the barrel,” Stone wrote.

The Podesta emails were released less than an hour after the Post published a story about tapes of a lewd conversation Trump had on the set of “Access Hollywood,” offsetting one of the more damaging moments of the Trump campaign.

All of this raises questions about exactly what contacts Manafort, Stone, Corsi or others may have had with WikiLeaks prior to the release of hacked emails; what they may have told Trump about it; and whether the campaign gave any advice on the timing of the release.

What will happen to the confidential report Mueller is supposed to file?

Mueller is required to create a confidential report “explaining the prosecution or declination decisions” at the end of the investigation, but it remains to be seen whether that report will be made public.

Once the report is completed, the Department of Justice has the authority to decide whether or not the findings will be released.

Such a report could have momentous consequences. Democratic leaders, including likely House speaker Nancy Pelosi, have said that they would only move forward on impeachment proceedings if such a report offers damning evidence against the president.

Congress could step in to make sure that the special counsel finding’s are released, according to Bob Bauer, who served as White House Counsel under President Barack Obama. Congress could require a report to be released in the event the special counsel is fired, or could change the Justice Department’s special counsel rules.

Alternately, some legal analysts think Mueller may find other ways to get his findings into the public record, as he has done with unusually detailed indictments of the Russian hackers and Cohen’s updated plea agreement.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.