COLUMBUS, Ohio — Marijuana growing operations were discovered at some of the crime scenes where officials said eight family members were killed in a “pre-planned execution,” raising more questions as authorities scrambled to find a suspect or suspects in the slayings in a rural southern Ohio community.

The killings at four homes near the small community of Piketon on Friday was “a sophisticated operation,” Attorney General Mike DeWine said at a news conference Sunday. Seven adults and one teenage boy were found shot in the head; three young children were not harmed.

“This was a pre-planned execution of eight individuals,” DeWine said.

Authorities remained tight-lipped Sunday about details of the investigation, any suspects or motives for the crime. They said they found marijuana operations at three of the crime scenes, but didn’t say if the deaths were linked to pot. Autopsies were expected to be completed Monday.

Pike County Sheriff Charles Reader said it was clear the family was targeted, and he’s told the victims’ relatives to arm themselves.

Reader said he didn’t believe safety was an issue for others, but he said “If you are fearful, arm yourself.”

Investigators have interviewed between 50 and 60 people in hopes of finding leads, and a team of 38 people is combing wooded areas around the shooting scenes to ensure no evidence was missed, authorities said.

“This was very methodical. This was well planned. This was not something that just happened,” said Reader, noting most victims were targeted while they were sleeping.

The victims were identified Saturday as 40-year-old Christopher Rhoden Sr.; his 16-year-old son, Christopher Rhoden Jr.; 44-year-old Kenneth Rhoden; 38-year-old Gary Rhoden; 37-year-old Dana Rhoden; 20-year-old Clarence “Frankie” Rhoden; 20-year-old Hannah Gilley; and 19-year-old Hanna Rhoden.