WASHINGTON: The Ohio massacre of eight family members in execution-style killings was a “sophisticated operation” that will require a lengthy investigation, officials said on Sunday. The murders this week in the village of Peebles – a rural community 80 miles (130 kilometers) east of Cincinnati – were “well-planned out and thought-out,” Ohio Attorney General Mike DeWine told reporters during a news conference. Police found seven bodies, each with a bullet to the head, in three separate homes on Friday. An eighth body was found later at a separate site. Several victims were apparently asleep in bed when they were killed. The shooters appeared to have spared a baby just four days old, who was found lying next to her dead mother, the authorities said. Another baby aged six months and a three-year-old child also survived. No arrests had been made, the officials said, declining to indicate whether they had identified any suspects or to name any possible motives.