No arrests have been made in the Ohio shooting investigation of eight execution-style killings of members of the Rhoden family last week in Pike County, Ohio.

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Large-scale marijuana grow operations were discovered at three of the four murder scenes.

Ohio Attorney General Mike DeWine told the Dayton Daily News on Monday that the possibility of a Mexican drug cartel connection has not been ruled out and that investigators are looking at everything.

Here are four possible motives:

Mexican drug cartel

In 2010, state officials announced the seizure of 22,000 marijuana plants in the village of Latham -- 15 miles west of Piketon -- and said they suspected a connection to Mexican drug cartels.

In August 2012, Ohio law enforcement officers found "a major marijuana grow site in Pike County with suspected ties to a Mexican drug cartel," according to a news release that DeWine's office issued at the time. Investigators said they discovered about 1,200 marijuana plants, which were destroyed, and they also found evidence of two abandoned campsites that they believe belonged to Mexican nationals.

The marijuana grow operations that authorities discovered appeared to be for commercial use and not personal use.

“We’re running these leads out,” DeWine told CBS News. “But there’s many different theories.”

The marijuana grow operations were not simply a few random plants in a field somewhere, the Columbus Dispatch reported from an interview with Pike County Prosecutor Rob Junk. He told Dispatch reporters that at least one was indoors and there appeared to be several hundred plants.

“It wasn’t just somebody sitting pots in the window,” Junk told the Dispatch.

"CBS This Morning" reported that the street value of the marijuana found is nearly $500,000.

“There’s a drug problem in most areas around here,” Pike County Sheriff Charles Reader said.

Family feud

The identities of the eight people killed are Hannah Gilley, 20; Christopher Rhoden Sr., 40; Christopher Rhoden Jr., 16; Clarence "Frankie" Rhoden, 20; Dana Rhoden, 37; Gary Rhoden, 38; Hanna Rhoden, 19; and Kenneth Rhoden, 44.

While nothing has been ruled out, it is unlikely that it was a random act of violence or a crime committed by another member of the Rhoden family, authorities said.

“This is a pre-planned execution of eight individuals. 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,” DeWine said. “We don’t know if it was one or two (shooters).”

Reader said the victims did not have previous criminal contact with his office.

Seven of the victims were found in three Union Hill Road homes in Piketon, while the eighth was found within a 10-minute drive from the other victims, most of whom were executed while they were in bed. All were killed during the nighttime hours.

Three children -- a 4-day-old, a 6-month-old and a 3-year-old -- were found unharmed at the scenes.

At Sunday’s news conference, Reader said he warned other Rhoden family members to be on guard.

Leonard Manley, the father of victim Dana Rhoden, called whoever committed the murders “a bunch of scumbags” who know the family.

“Whoever done it knows the family,” Manley said. “(Because) there were two dogs there that would eat you up. But I ain’t going to say no more.”

Manley, who is still shaken up about the the loss of this relatives, said his daughter was a kind person who would “give you the shirt off her back,” and people in the area were aware of her kindness.

He learned about the deaths Friday morning from another one of his daughters, who discovered the victims and called him, Manley said, noting that he’s taken the sheriff’s advice and has armed himself.

Facebook threat

DeWine said his office has “received over 100 tips, conducted over 50 to 60 interviews (and) over 100 personnel were involved in this investigation.”

Two of those individuals interviewed were Isaiah Jones and Rusty Mongold.

Jones told CBS News that he was detained at gunpoint during a traffic stop. He was questioned for six hours, then released.

“I really want people to know I had nothing to do with it,” a tearful Jones said. “These were also friends of mine and that I went to school with.”

Mongold, Jones’ friend, said in a Facebook post that he had nothing to do with the shooting and that he went to the sheriff’s office to clear his name and submit a DNA sample.

The recent Facebook post stemmed from an April 12 Facebook post that alluded to a “kid that hit (Mongold) with his car” and wanting to “beat his skull in,” a perceived threat against the youngest murder victim.

A commenter asks if it’s Chris Rhoden, and Mongold responds, “Yes.”

Cockfighting ring

DeWine said that he can’t definitively say that the Rhoden family was involved in cockfighting.

But when he visited one of the crime scenes Friday, he said he noticed roosters in cages that are normally associated with cockfighting.