Search underway for killer of eight people in U.S. Midwest state of Ohio

Investigators are still trying hard Sunday to find out a killer or killers who were allegedly targeting a tight-knit family in southern state of Ohio and shooting dead eight of the family members.

The shootings, which happened at four separate homes in Piketon, rural southern Ohio Friday, were "pre-planned" and carried out with precision, said Ohio Attorney General Mike DeWine at a press conference held Sunday.

"This is a pre-planned execution of eight individuals," DeWine said at the press conference. "We don't know if it was one or two (shooters)."

"It was a sophisticated operation and those who carried it out were trying to do everything they could do to hinder the investigation and their prosecution," he said, warning that the probe will be a lengthy process. More than 100 personnel had been involved in the investigation.

All of the victims were members of the Rhoden family. They were found fatally shot Friday at four locations in Piketon County, about 96 kilometers south of Columbus, the state's capital, each killed by an execution-style gunshot wound to the head.

Authorities said none of the injuries appeared self-inflicted. Three children, aged four days, six months and three years, were found unharmed at the scenes.

No arrests have been made so far, said DeWine. Endit