Gunmen opened fire inside a crowded Brooklyn, N.Y., social club during a dance, killing two people and injuring 13 others, police said. Investigators believe there were five gunmen because they found evidence that 100 bullets were fired from five weapons, including a .30-caliber rifle, police Lt. Anthony Mara said. No weapons were recovered, and no arrests have been made. The shootings occurred at the Esquire Hall Social Club, where a promoter had promised "tight, tight, tight security" for the party, because of the reputed tough neighborhood. Between 300 and 400 people, most of them in their 20s, were at the dance when the violence broke out, police said.