A gunman wearing a shield and a gun opened fire in downtown Dayton, Ohio on Sunday, killing nine of his sister and wounding 27 others, the second casualty in less than 24 hours, authorities said.
Police and the mayor of Dayton said officers on a regular patrol near the scene arrived at the scene in less than a minute and shot dead the attacker, probably without causing more casualties.
"The officers moved ... immediately and ended this in 30 seconds," police chief Richard Beale told a news conference.
Police said the gunman was Conner Bates, a 24-year-old white man from Belbrück, Ohio, who said he was armed with a rifle with a safe that could carry a hundred bullets.
Police said he was wearing an earguard and a hunting rifle in his car.
His sister, Megan Bates, 22, was among the first victims to die, and Bail said the two brothers had arrived in the same vehicle with a third facility earlier in the evening but separated before the massacre. He added that the facilities were shot.