Watch Live: Authorities giving updates on deadly mass shooting at Fourth of July parade in Highland Park, Illinois

Authorities plan to give an update Tuesday on the deadly shooting at a Fourth of July parade in Highland Park, Illinois. A gunman attacked paradegoers from a rooftop during the Chicago suburb's Independence Day festivities Monday, killing at least six people and injuring dozens more.

Police arrested a man described as a person of interest in the rampage Monday evening. Robert "Bobby" Crimo III, 22, was taken into custody without incident, authorities said.

Nicolas Toledo, who was in his late 70s and visiting from Mexico, was among the victims, his family said. Also killed was Jacki Sundheim, a staff member at nearby North Shore Congregation Israel, which announced her death on its website.