(Reuters) - U.S. Special Counsel Robert Mueller and other federal prosecutors have been investigating whether President Donald Trump’s 2016 campaign conspired with Russia and whether the president unlawfully tried to obstruct the inquiry.

FILE PHOTO: U.S. President Donald Trump's son, Donald Trump Jr. speaks during a campaign event for Republican congressional candidate Rick Saccone at the Blaine Hill Volunteer Fire dept. in Elizabeth Township, Pennsylvania, U.S. March 12, 2018. REUTERS/Brendan McDermid/File Photo

Mueller has handed in the keenly awaited report on his probe, the Justice Department said on Friday.

U.S. intelligence agencies have concluded Russia interfered in the presidential election with a campaign of hacking and propaganda to sow discord in the United States and damage the Republican Trump’s Democratic opponent, Hillary Clinton. Russia denies it. Trump has denied collusion and obstruction of justice.

Here are some key figures in the investigation:

DONALD TRUMP JR.

Trump’s eldest son set up a June 2016 meeting at Trump Tower in New York with a Kremlin-linked lawyer, Natalia Veselnitskaya, and other Russians who had offered damaging information on Clinton. In an email after being promised the Clinton “dirt,” Trump Jr. wrote “I love it.” When news of the meeting broke in July 2017, Trump Jr. issued a statement saying the meeting was set up to discuss adoption policy, not politics, before later admitting he had been expecting intelligence on Clinton.

President Trump’s advisers eventually said the president dictated the misleading statement put out in his son’s name, after initially denying his involvement.

JARED KUSHNER

Trump’s son-in-law has served as a senior adviser to him as both candidate and president. Kushner initially did not list any Russian contacts on his application for a White House security clearance, but subsequently revised those forms to reveal he had participated in the June 2016 Trump Tower meeting and discussed setting up a secure communications line at the Russian Embassy in Washington after Trump won the November 2016 election with Sergei Kislyak, then-Russian ambassador to the United States.

JEFF SESSIONS

Sessions, a longtime U.S. senator from Alabama, served as a campaign adviser and then Trump’s first attorney general. During his Senate confirmation hearings he said he did not meet with Russian officials during the campaign, but later admitted he had met at least twice with Kislyak. Under pressure, he recused himself from oversight of the Russia investigation, which at the time was led by the FBI and later by Mueller. The recusal angered Trump, who eventually fired Sessions last November.

MICHAEL FLYNN

A retired U.S. Army lieutenant general, Flynn was a top campaign adviser and served as Trump’s first national security adviser until he was fired after only weeks on the job for lying about his conversations with Kislyak in December 2017, after Trump won the election but before he took office. Flynn discussed U.S. sanctions with Russia and asked the ambassador for help with a U.N. vote, according to court filings. Flynn pleaded guilty to lying to the FBI and has been cooperating with investigators.

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Before he joined Trump’s campaign, Flynn sat next to Russian President Vladimir Putin at a Moscow dinner in December 2015 celebrating RT, a pro-Kremlin Russian-owned English language media channel.

PAUL MANAFORT

Manafort served on Trump’s campaign from March to August 2016, including three months as chairman, ensuring Trump secured the Republican presidential nomination during the party’s convention in Cleveland. During that time, the Republican Party softened its support for arming U.S. allies in Ukraine.

He participated in the Trump Tower meeting with Russians who offered damaging information on Clinton.

Manafort’s lawyers said that after the convention he shared election polling data and discussed a way to end the Ukraine conflict with Russian Konstantin Kilimnik, a former business associate who Mueller’s team has called an agent of the Kremlin.

Manafort was sentenced to 7-1/2 years in prison on March 13 in two cases prosecuted by Mueller. He was found guilty in Virginia of bank and tax fraud related to millions of dollars he earned as a political consultant for pro-Russian politicians in Ukraine. He pleaded guilty in Washington to two conspiracy charges. A judge ruled on Feb. 13 that Manafort violated his plea agreement with prosecutors by repeatedly lying to Mueller’s team.

Less than an hour following his sentencing, the former campaign chairman was charged with residential mortgage fraud and other felonies in New York. State lawmakers moved to ensure Manafort can be prosecuted even if he receives a presidential pardon. nL1N21014A]

RICK GATES

Manafort’s longtime lobbying associate served as deputy campaign chairman and worked on the transition after Trump was elected. Gates pleaded guilty to lying to investigators and was a star witness in Manafort’s 2018 trial, testifying that he helped his boss file false tax returns and hide millions of dollars offshore. Gates has continued to cooperate with the investigation, according to court filings.

MICHAEL COHEN

Trump’s former longtime personal attorney once boasted that he would take a bullet for his boss, but has since turned on him. In a series of guilty pleas, Cohen said he worked on a deal to build a Trump tower in Moscow for nearly a year while Trump was running for president, and acted at Trump’s direction to break campaign-finance laws by arranging “hush money” payments to women who claim to have had sexual relationships with Trump. Cohen’s turn against Trump was on dramatic display in his congressional testimony on Feb. 27, accusing the president of being a “racist,” “conman” and “cheat.” Cohen is due to begin serving a three-year prison sentence on May. 6.

ROGER STONE

Stone is a self-proclaimed political “dirty trickster” who has known Trump for about four decades. Stone is accused of telling members of Trump’s presidential campaign that he knew in advance of plans by the WikiLeaks website to release damaging emails about Clinton. Cohen has said he heard Stone tell Trump on the telephone in July 2016 about a forthcoming release by WikiLeaks of the stolen emails.

U.S. intelligence agencies have concluded the emails were stolen by Russians. They sowed division among Democratic voters by showing that Democratic Party officials had favored Clinton over insurgent candidate Bernie Sanders. Stone pleaded not guilty in January to charges brought by Mueller.

INTERNET RESEARCH AGENCY

Muller’s team has said this St. Petersburg-based organization tried to influence the 2016 U.S. presidential election through fake social-media accounts, aiming to spread distrust about the candidates and the American political system. The organization employed hundreds of people, according to an indictment.

RUDY GIULIANI

The former New York mayor and 2008 Republican presidential candidate has offered a freewheeling defense of the president in the news media since signing on as Trump’s personal lawyer in April 2018. Giuliani has occasionally misstated facts, drawing rebukes from Trump or other members of his administration.

MARIA BUTINA

This Russian woman, a former graduate student at American University in Washington, has admitted to trying to infiltrate the influential National Rifle Association lobby group and make inroads with conservative activists and Republicans as an agent for Moscow in a criminal case in parallel with the Mueller investigation. Butina pleaded guilty to a conspiracy charge in December 2018 and has agreed to cooperate with U.S. investigators.

JAMES COMEY

As FBI director, Comey oversaw the initial stages of the Russia investigation until Trump fired him in May 2017. The White House initially said Comey was fired because he had mishandled a 2016 investigation into Clinton’s emails, but shortly thereafter Trump told NBC that he had “this Russia thing” on his mind in the dismissal. Comey has said that Trump pressured him to end the investigation of Flynn.

CARTER PAGE

The Trump foreign-policy adviser met with Russian officials in Moscow in July 2016, and has said he reported back to Sessions and other senior campaign officials after the trip. His contacts attracted suspicion from the FBI, which said in surveillance applications that it believed Page “has been collaborating and conspiring with the Russian Government” and had established relationships with Russian intelligence officers. Page, who has not been charged, has said he did nothing wrong.