WASHINGTON (AP) — A look at some of the key players in the Trump-Russia probe after a federal indictment charged 13 Russians in a plot to interfere in the 2016 US presidential election:

PUTIN'S CHEF

One of the key figures indicted with plotting to interfere in the 2016 U.S. presidential is a Russian restaurateur believed to have ties to President Vladimir Putin.

An entrepreneur from St. Petersburg, Yevgeny Prigozhin has been dubbed "Putin's chef" by Russian media because his restaurants and catering businesses have hosted the Kremlin leader's dinners with foreign dignitaries. In the more than 10 years since establishing a relationship with Putin, Prigozhin's business has expanded to services for the military.

Prigozhin's assets also include an oil trading firm that reportedly has been sending private Russian fighters to Syria. Prigozhin is on the list of those sanctioned by the U.S.

In comments to Russian state news agency RIA Novosti, Prigozhin dismissed the indictment.

"Americans are very impressionable people," he was quoted as saying. "They see what they want to see."

THE TROLL FACTORY

Based in St. Petersburg, Putin's hometown, the Russian Internet Research Agency employs bloggers and online commentators to influence public opinion in Russia and abroad.

The indictment says that the company was funded by Prigzhin and that it purchased internet advertisements in the names of Americans whose identities they had stolen, staged political rallies while posing as American political activists and paid people in the U.S. to promote or disparage candidates. They started out by posting pro-Russian or controversial comments on social media and popular web sites and then developed more sophisticated tactics.

Analysts and journalists found that some of the accounts — such as the now-deleted and rabidly pro-Trump @TEN_GOP — accrued national followings and were retweeted by a range of figures as well as several members of Trump's team, including ex-National Security Adviser Gen. Michael Flynn, Trump campaign manager Kellyanne Conway and one of Trump's sons, Donald Trump Jr.

Soon enough, they were also organizing flesh-and-blood protests on American soil and being promoted by some of the most senior politicians in the land.

'UNWITTING' INDIVIDUALS

Some Trump campaign officials also helped the Russian meddling — unknowingly, the indictment says. Some of the defendants posed as Americans and communicated with "unwitting individuals" associated with the Trump election team in order to coordinate activities, according to the document. Sometimes the Russians used fake U.S. personas co communicate with Trump officials doing local outreach and those officials would then distribute their materials via social media. There was no immediate comment from the White House on this matter.

HOW ONE RUSSIAN OPERATED

The FBI's indictment carries new tidbits about how its operatives stole Americans' Social Security numbers and drivers' licenses to help pull off their fakery.

It appears that the FBI had access to the group's internal communications. In the case of agency worker Irina Kaverzina, for example, the FBI cites an email she wrote to her family saying: "We had a slight crisis here at work: the FBI busted our activity (not a joke). So, I got preoccupied with covering tracks together with the colleagues." Later, Kaverzina goes on: "I created all these pictures and posts, and the Americans believed it was their people."

THE CHIEF OF THE INVESTIGATION

Robert Mueller was appointed FBI director shortly before the Sept. 11, 2001, terror attacks and stayed on in the position for the next 12 years, transforming the bureau into a national intelligence agency. He retired from government in 2013 and joined a private law firm where he conducted high-profile investigations. He was appointed special counsel on May 17, 2017, by Deputy Attorney General Rod Rosenstein.