Police said the complainant, Amanda Byrnes, of Thomaston, contacted officers expressing fear regarding the actions of another driver, Jamel Shepherd, of New Haven. Investigators determined that the altercation began over a dispute about driving behavior while both vehicles were traveling north on Main Street near Dollar General, police said. Police said they determined that Byrnes called Shepherd a racial slur during a verbal exchange, and that Shepherd subsequently threw a beverage at Byrnes’ vehicle. Police said Shepherd provided a video capturing the use of the racial slur, and that Byrnes alleged that Shepherd threatened her life when she attempted to record him with her phone. “Officers conducted a comprehensive canvass of nearby local businesses for witnesses and video surveillance, which yielded negative results at the scene,” police said. Police said Byrnes was charged with second-degree breach of peace and Shepherd was charged with second-degree threatening. They were each issued a summons for an Oct. 14 court date. “The Watertown Police Department takes incidents of this nature seriously and remains committed to a thorough and complete investigation,” police said.