The attack occurred shortly after a Riesel radio broadcast. Barry Gray, radio station WMCA's overnight talk radio host, had asked Riesel to substitute for him. Riesel invited two IUOE Local 138 leaders who were challenging the DeKonings for control of the local union to join him for the broadcast. The broadcast originated from Hutton's Restaurant at 47th Street and Lexington Avenue shortly after midnight on April 5, and concluded at 2 AM. Afterward, Riesel and his secretary went to Lindy's restaurant, located on Broadway between 49th Street and 50th Street. They had coffee, and departed Lindy's at 3 AM to walk to the secretary's automobile. Riesel removed his eyeglasses, which he did by habit when in public. A slender, black-haired man in blue and white jacket stepped out of the shadows of the entrance to the Mark Hellinger Theatre and threw a vial of sulphuric acid into Riesel's eyes. Riesel shouted, "My gosh! My gosh!", and clutched at his face. While the secretary and others rendered assistance and dragged Riesel into Lindy's, the assailant walked calmly away.