Patrons at a restaurant acted quickly and selflessly to stop a gunman who opened fire while a wedding was taking place at a New Hampshire country club, averting a worse tragedy, authorities said Sunday. The gunfire killed Robert DeCesare Jr., 59, at Sky Meadow Country Club in Nashua, said New Hampshire Attorney General John Formella and Nashua Police Chief Kevin Rourke. They said the suspect was Hunter Nadeau, 23, of Nashua, and that he had been arrested and charged with one count of second-degree murder for knowingly shooting DeCesare. “Additional charges likely will be brought, including for the additional shooting victims,” Formella and Rourke said in a statement. The bride had just come up to me and gave me the plates to say, ‘All right, you give this to my husband.’ And all of a sudden we heard ‘pop, pop, pop, pop, pop.’ Heard five shots,” Flabouris said.