US special counsel Robert Mueller has concluded his investigation into Russian interference in the US presidential election and delivered his final report to Attorney General William Barr.

Here’s what to expect next:

What happens when the investigation ends?

Mr Mueller had to submit a report of some kind. It could be bare-bones.

Justice Department regulations require only that Mr Mueller give the Attorney General a confidential report that explains the decisions to pursue or decline prosecutions. That could be as simple as a bullet point list or as fulsome as a report running hundreds of pages.

What will the Attorney General do?

William Barr said he envisions two reports, and only one for congressional and public consumption.

Mr Barr has said he takes seriously the “shall be confidential” part of the regulations governing Mr Mueller’s report. He has noted that department protocol says internal memos explaining charging decisions should not be released.

During his confirmation hearing, Mr Barr said he would draft, after Mr Mueller turned in his report, a second one for the chairman and ranking members of the House and Senate Judiciary committees. But the regulations provide little guidance for what such a report would say.

The Attorney General is required only to say the investigation has concluded and describe or explain any times when he or Deputy Attorney General Rod Rosenstein decided an action Mr Mueller proposed “was so inappropriate or unwarranted” that it should not be pursued.

In a letter Mr Barr sent on Friday to the four members of the two Judiciary committees, he said there were “no such instances”. He also said he may be in a position to advise them of Mr Mueller’s conclusions “as soon as this weekend”.

Mr Barr indicated that he expects to use his report to share the results of Mr Mueller’s investigation with the public, which the regulations allow him to do. But he has hedged on specifics and said his plans could change after speaking with Mr Mueller and Mr Rosenstein.

Will Donald Trump be able to see the report?

Donald Trump
It is not yet clear whether Donald Trump will get to see the report (Carolyn Kaster/AP)

It is unclear whether Donald Trump will ask to see the report and under what circumstances he or his attorneys might be able to view it, especially because the document is meant to be confidential for Justice Department leadership.

Mr Mueller reports to the Justice Department, not the White House.

Mr Barr said at his confirmation hearing that he would not permit White House interference in the investigation. But he has also voiced an expansive view of executive power in which the president functions as the country’s chief law enforcement officer and has wide latitude in giving directives to the FBI and Justice Department.

Democrats could seize on any disclosure to the president to argue that the report is not confidential and should be immediately provided to them as well.

Can Democrats in Congress subpoena Mr Mueller and his report?

Yes. The chairman of the House Judiciary Committee, Representative Jerrold Nadler, has said as much.

“We could subpoena the final report. We could subpoena Mueller and ask him in front of the committee what was in your final report. Those are things we could do,” Mr Nadler told ABC’s This Week in October.

But Mr Trump, as the leader of the executive branch, could direct the Justice Department to defy the subpoena, setting the stage for a court fight that would almost certainly go to the Supreme Court.