In December 2018, Peterson filed a $100 million defamation lawsuit in the U.S. District Court for Massachusetts against the Arizona Republic, parent company Gannett, reporter Craig Harris, and Dennis Burke, a former business colleague Peterson accuses of orchestrating an allegedly factually incorrect newspaper article as part of a "ongoing retaliatory campaign." According to Peterson's lawsuit, Burke, who resigned in 2011 as U.S. Attorney for the District of Arizona amid allegations of misconduct, had a history of improper retaliation against coworkers and attempted to manipulate the press by leaking documents in the Obama-era Operation Fast and Furious scandal. Peterson attributed his lawsuit against Burke to "a disgruntled former colleague who is a former federal prosecutor apparently willing to use his knowledge of prosecutorial methods to implement various schemes based on lies, innuendo and half truths meant to destabilize our business projects and create the false appearance of wrongs in order to cover up Burke's own bad acts."