BREAKING NEWS: Second Deadly US Mass Shooting in Less Than 24 Hours; 9 Killed and 27 Injured in Dayton, Ohio

Nine people were killed when a shooter opened fire in Dayton, Ohio early Sunday.

Responding officers also fatally shot the gunman, later identified by police as 24-year-old Connor Betts of Bellbrook, Ohio. Betts used an assault-style rifle, a .223 caliber weapon with high capacity magazines and wore body armor during the shooting.

Authorities said Megan Betts, who was killed in the shooting, was the suspect’s sister.

Police responded to the shooting in under a minute early Sunday on the streets of downtown Dayton’s Oregon District, a historic neighborhood home to bars, restaurants and theaters.

This was the second mass shooting in US in less than 24 hours. In El Paso, Texas, a gunman left 20 people dead and more than two dozen others injured on Saturday.

El Paso shooting suspect Patrick Crusius, 21-years-old, is cooperating with investigators and told them he acted alone in carrying out his attack, according to a law enforcement source, says CBS News. Crusius told them his attack was motivated by his objection to Hispanic immigrants, the source said.

Crusius has been charged under state law with capital murder but has not been charged at this time with a federal crime. El Paso District Attorney Jaime Esparza announced Sunday that prosecutors will seek the death penalty for Patrick Crusius.

Multiple law enforcement officials told CBS News there is not a hate crime nexus yet in the Dayton shooting.

As of Sunday, which was the 216th day of the year, there have been 251 mass shootings in the U.S., according to data from the nonprofit Gun Violence Archive, which tracks every mass shooting in the country. The Gun Violence Archive defines a mass shooting as any incident in which at least four people were shot, excluding the shooter.