It was being run by Mexicans who were staying in a

Investigators revealed they found a marijuana growing operation in three of the four houses where the shootings took place

are gathering evidence in a bid top track down the gunman

Prosecutors are investigating a Facebook threat that mentioned one of the eight family members killed execution-style by a rampaging gunman in Ohio.

The message was directed at Christopher Rhoden Jr, 16, who was slayed along with seven relatives in a spree of shootings across four rural locations in Pike County on Friday.

What was said in the message and who sent it has not been revealed.

The post is just one piece of evidence prosecutors have gathered as they continue their bid to track down the gunman.

The development in the case comes after authorities also revealed the area where the Rhodens were murdered has historic ties to Mexican drug cartels.

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Prosecutors are investigating a Facebook threat that mentioned one of the eight family members killed execution-style by a rampaging gunman in Ohio. The message was directed at Christopher Rhoden Jr, 16, (pictured) who was slayed along with seven relatives on Friday

In August 2012, a major marijuana growing site with more than 1,200 plants was discovered.

Police also found two abandoned campsites where Mexicans were believed to have been staying.

Ohio Attorney General Mike DeWine said he was aware of the social media threat. The content of the message and the sender have not been disclosed

It's not known whether the operation is linked to the slayings, or whether there are still ties to cartels in the area.

Ohio Attorney General Mike DeWine told CBS News: 'I'm aware of the Facebook threat.

'Every piece of information is valuable and our investigators are certainly taking that into consideration.'

On Sunday it was revealed the Rhoden family were involved in drugs and were growing marijuana.

Detectives uncovered marijuana ‘grow operations’ in three of the four houses where the victims were shot dead.

Police were also scouring woodland around the rundown area for any further drugs, where confederate flags fly and locals wear T shirts proclaiming their ‘Red Neck’ beliefs.

Police believe there may be further evidence of drug production by the Rhoden family and are examining whether the massacre was fueled by a turf war.

Despite the unearthing of cannabis operations, Pike County Sheriff Charles Reader stated that the family were not known to him through criminal activity and he had been an officer in the area for more than 20 years.

Ohio Attorney General Mike DeWine said: ‘Marijuana has been found in three locations at crime scenes. They were grow operations.’

He said the murders had been well planned and amounted ‘to a pre-planned execution.’

He added: ‘This is not your case where someone's got mad at someone and shot them.

‘It was a sophisticated operation. And those who carried it out were trying to do everything that they could do to hinder the investigation and their prosecution.’

The development in the case comes after authorities revealed the area where the Rhodens were murdered has historic ties to Mexican cartels. Above, an aerial view of one of the scenes on Friday

Husband-to-be Frankie Rhoden and his fiancee Hazel Gilley, 20, were among those killed Friday in Piketon, Ohio, according to the Morning Ledger

Tragic: Grandmother-to-be Dana Lynn Rhoden (left), 37, and her son, 16-year-old Chris were also murdered, according to the Morning Ledger. Victims Chris and Frankie are brothers

Reader added: 'This was very methodical. This was well planned. This was not something that just happened.'

The eight victims were Christopher Rhoden Sr, 40, 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.

Reader said it was evident that it was only members of the family who were targeted and the general public were not likely to be threatened.

He added: 'I’m a member of that community, it’s very emotional to find out that 8 people in your community have been murdered.'

Eighteen pieces of evidence were being examined for DNA clues, DeWine said, but he would not reveal what they were.

Police also refused to reveal what type of gun or bullets were used and whether they had identified a suspect.

Authorities have been scrambling to determine who targeted the clan and why. Investigators have interviewed between 50 and 60 people in hopes of finding leads, and a team 38 people is combing wooded areas around the shooting scenes to ensure no evidence was missed, Reader said.

Five search warrants have been issued and seven of the eight autopsies have been completed.

Police are also looking at claims by Rhoden family members that twenty-year-old Frankie Rhoden felt threatened by rivals jealous of his $3000 demolition derby car which he used to enter competitions, as first revealed by Daily Mail Online.

More than 100 members of the Rhoden family, some of whom live in rundown houses and trailers dotted around the area were advised to ‘arm themselves’ by Reader for their own safety.

Devastating: Hanna May Rhoden (pictured left and right) was killed Friday in the Piketon shooting that has rocked the small community, according to the Morning Ledger. Her Facebook page says she was already a mother to one child

He warned members of the Rhoden family: ‘If you are fearful – arm yourself’ although he later said he was not directly asking them to defend themselves with guns.

He added: ‘I have told the Rhoden family to be armed. If any other citizen feels that they are in jeopardy, I would advise them to do the same.’

Many of the Rhodens have been taking shelter in a local church and were described by witnesses as being 'scared for their lives'.

Members of the family of the slain victims previously put forward the theory that jealousy or a dispute over Frankie Rhoden's $3,000 car could be behind the murders.

Frankie Rhoden, 20, who was gunned down with his fiancée Hannah Hazel Gilley, also 20, was said to have spoken about bitterness between him and other competitors.

He had competed several times in his 1990s model Ford Crown Victoria car in local derbies and had told of angry rows with other competitors.

He had used his car to ‘smash up’ the vehicles of other drivers, with the last car standing being declared the winner, in several local rallies.

Kenneth Rhoden (left), 44, and Chris Rhoden Sr (right), 40, were named as victims in Friday's murders. Chris Rhoden Sr is the father of Chris Rhoden Jr, who was also killed in the massacre

Johnny Gambill, whose wife Lorretta was first cousin to Dana Lynn Rhoden, 37, said: ‘Some of us have been talking about the jealousy that Frankie had faced over his car.

‘It was worth more than $3,000 and that made some people jealous around Piketon.’

Gambill, a trash collector, added: ' My wife had spoken to Dana about it and we feel today that could be the reason because there ain’t nothing else that seems what it could it be.

‘The Rhodens are good people who live for each other and there is no reason why anybody should want to do this. They are all very close.

‘There is no drugs reason or money reason. Everybody is peaceful around here normally. There ain’t never been anything at all like this.

‘The whole thing is so shocking and if the car was the reason then that is so disgusting and incredible. But there were people jealous about him and his car.’

Russ Clark, who runs ‘Smash It Demolition Derbys’ locally with his brother Tim, said Frankie Rhoden’s car was worth more than many of the cars used in tournaments.

Gary Rhoden (pictured above in an undated photograph), 38, was named as one of eight family members killed in Pike County on Friday

He told Daily Mail Online that most cars were valued at around $500 to $1000 with high end cars worth from $2000 upwards. The victim’s car ‘would easily be worth $3000’ he added.

Demolition derbies are popular across the Midwest, and Frankie Rhoden had featured his car in local demolition derbies.

The events are popular in the area and attract thousands of spectators, but competitions are governed by strict rules and drivers have to wear safety helmets.

Gambill added: ‘The whole thing is horrible. The Rhodens are good people and I hope the police catch the people who did this soon.'

But he insisted that the massacre should not give credence to calls for stronger gun laws to be introduced in the United States.

He added: ‘Guns don’t kill people, it is people. I have got guns because I go hunting, but I would never point one at anybody.’

In a 911 call following the shootings, a woman sounded out of breath as she frantically told a dispatcher, 'I think my brother-in-law's dead ... There's blood all over the house.'

'There's blood all over the house. My brother-in-law is in the bedroom and it looks like someone has beat the hell out of him,' she said.

Before weeping into the phone, she says it looked as though someone else was dead too.

The distraught woman said two men, Chris Rhoden and Gary Rhoden, at 4077 Union Hill Road appeared to be dead during the call that was placed at 7.49am Friday.

She drove to the house and discovered the horrific scene.

'I think they are both dead,' she said.

In a second 911 call that was received, a man said: 'I just found my cousin with a gunshot wound.'

Members of the family of the victims suggested that jealousy or a dispute over a $3,000 demolition derby car (pictured) driven by Frankie Rhoden could be behind the murders.

The dispatcher asks, 'Is he alive?'

The man replied and said 'no, no'.

Local Pastor Phil Fulton, whose church housed up to 100 Rhoden family members and allied relations, said: ‘The people who did this are evil, sick, hideous.’

He said he had seen the family members together and they were weeping and in fear for their safety.

Daily Mail Online was able to reach the family at the church, but they were too upset to talk and asked, through police and church officials, for photographs of them not to be published because of safety fears.

Police have established that the killer or killers are still at large and not among the eight victims.

The horrific massacre has rocked the small community to its core. Authorities spoke to 100 of their relatives and friends gathered at a church on Friday.

During a news conference on Friday evening, DeWine said authorities have interviewed more than 30 people and will talk to more of them as the investigation continues.

'We will continue until the case is solved. We do not know whether we're talking about one individual or two or three or more,' DeWine added.

No person of interest has been apprehended and investigators are looking at different theories.

They believe the killers targeted the family specifically, and DeWine said there was no indication of a threat towards the rest of the community.

The rest of the family has been in touch with the sheriff's office for their protection.

Kimberly Newman, Victim Advocate and Program Director for the Adams County Victim Assistance Program, told reporters that the family is expressing gratitude for the support and prayers they've received.

'The Rhoden family would like to thank everyone for all the outpouring of prayers and support for their family,' the statement reads.

'They ask that you continue to keep them in their prayers. They want to thank all law enforcement from Pike County and all surrounding counties for their immediate response.'