Jeffrey Wertkin had a plot to bring in business and impress his new partners after joining one of Washington’s most influential law firms. As a former high-stakes corporate-fraud prosecutor with the Department of Justice, he had secretly stockpiled sealed lawsuits brought by whistleblowers. Now, he would sell copies of the suits to the very targets of the pending government investigations — and his services to defend them. ... Wertkin has admitted hawking sealed files he spirited out of the Justice Department’s civil-fraud division where he worked for six years until 2016. He walked out, court records state, with files for...