The youngest of the eight Ohio family members found slain in execution-style murders last week received a threat on Facebook before the mass killings, Ohio's attoey general said Monday.

Christopher Rhoden Jr., a 16-year-old freshman at Piketon High School, was the subject of the threat, CBS News reported.

"I'm aware of the Facebook threat," Ohio Attoey General Mike DeWine said. "Every piece of information is valuable and our investigators are certainly taking that into consideration."

The threat is just one emerging piece of evidence in the investigation, which has also uncovered cockfighting chickens and a marijuana growing operation at some of the properties where the eight were killed.

DeWine told The Cinciati Enquirer that investigators found roosters kept in individual cages, which he said was "consistent with" an illegal cockfighting operation. DeWine cautioned, however that investigators "don't know what's relevant" to the murders of members of the Rhoden family.

Also Monday, a local prosecutor confirmed that several hundred marijauna plants were found at three of the crime scenes, some of which were sheltered in a large grow-house.

"It wasn't just somebody sitting pots in the window," Pike County Prosecutor Rob Junk told The Columbus Dispatch.

All eight victims were fatally shot in the head, including a young mother whose newbo baby was sleeping beside her Friday moing. That baby, another infant and a toddler were spared.

Extensive marijuana-growing operations are not uncommon in sparsely populated rural southe Ohio, an economically distressed coer of Appalachia. Two of the four homes that became crime scenes Friday are within walking distance of each other along a remote, winding road leading into wooded hills from a rural highway. The others are nearby.

Piketon — about 60 miles south of Columbus and 90 miles east of Cinciati — is in Pike County, which is home to just 28,000 people and has an unemployment rate of 8.6 percent, considerably higher than Ohio's rate of 5.1. A main employer is a shuttered Cold War-era uranium plant whose cleanup provides hundreds of local jobs.

More than 22,000 marijuana plants were seized in Pike County in 2010, and while authorities made no arrests, they said they found two abandoned camps where Mexican nationals apparently stayed. In 2012, another 1,200 plants were seized in Pike County in an operation coected to a Mexican drug cartel, the Attoey General's office said. Seizures continued in 2013 and 2014 in the county.

The victims have been identified as 40-year-old Christopher Rhoden Sr.; his ex-wife, 37-year-old Dana Rhoden; their three children; Christopher Rhoden Sr.'s brother, 44-year-old Keeth Rhoden; their cousin, 38-year-old Gary Rhoden; and 20-year-old Haah Gilley, whose 6-month old son with "Frankie" was unharmed.

All eight autopsies have been completed.

DeWine said the state's crime lab was looking at 18 pieces of evidence from a DNA and ballistic standpoint, and that five search warrants have been executed. More than 100 tips have been given to investigators, and a Cinciati-area businessman offered a $25,000 reward for details leading to those responsible.

The Associated Press contributed to this report.