Special counsel Robert Mueller’s team of investigators probing the 2016 U.S. presidential race has grown to include Ryan Dickey, a federal prosecutor responsible for investigating several high-profile cybercrime cases.

Mr. Mueller’s team brought Mr. Dickey onboard in November, a spokesperson for the special counsel’s office confirmed Wednesday, adding him to a group of 16 other lawyers already investigating the 2016 race on behalf of the Justice Department, The Washington Post first reported.

Previously an assistant U.S. attorney in the Eastern District of Virginia and Department of Justice’s computer crime and intellectual-property division, Mr. Dickey is the first publicly known member of the special counsel’s probe to specialize exclusively in cyber matters, The Post reported.

Notably Mr. Dickey participated in the government’s investigations into defunct file-sharing website Megaupload and Marcel Lehel Lazar, a Romanian computer hacker better known by his online alias “Guccifer.”

The Justice Department charged Megaupload founder Kim Dotcom and six of his associates in 2012 in connection with operating a website the government blamed with facilitating wide-scale copyright infringement allegedly responsible for causing the entertainment industry more than $500 million in lost revenue. The Justice Department described it as “among the largest criminal copyright cases ever brought by the United States.”

Lehel, meanwhile, took credit for a hacking spree that targeted the email accounts of several high-profile victims including retired four-star general Colin Powell and Sidney Blumenthal, a confidant of former secretary of state Hillary Clinton, among others. He’s attributed with uncovering the existence of a private email address used by Mrs. Clinton in office, the likes of which spurred a federal investigation widely blamed with disrupting her 2016 presidential bid.

The U.S. intelligence community concluded last year that the Russian government interfered in the 2016 presidential election, and the special counsel’s office and four congressional committees are currently investigating both Moscow’s role in the contest as well as any links between Russia and the winner of the race, President Trump.

Russian operatives hacked into internet accounts associated with Mrs. Clinton’s unsuccessful 2016 presidential campaign, according to intelligence officials, and the special counsel’s office could be considering the possibility of pursuing hacking conspiracy charges against members of Mr. Trump’s inner-circle, The Post reported.

Mr. Trump has repeatedly denied colluding with Russia, and on Wednesday he referred to the special counsel’s investigation as the “single greatest Witch Hunt in American history.”

The DOJ’s case against Mr. Dotcom is still pending. Lehel pleaded guilty to computer hacking charges in 2016 and was subsequently extradited to his native Romania to finish serving a previously delivered prison sentence related to separate hacking charges.