A family of four has been arrested for the gruesome slayings of eight people from another family in rural Ohio two years ago.

George 'Billy' Wagner III, 47; his wife Angela Wagner, 48; and their two sons, George Wagner, 27, and Edward 'Jake' Wagner, 26, were all arrested on Tuesday in connection to one of the state's most notorious crimes.

The Wagners, from the rural southern Ohio village of Peebles, were all charged with planning and murdering the Rhoden family who lived in the neighboring village of Piketon, 11 miles away, back in April 2016.

Attorney General Mike DeWine revealed this week authorities believe that the murders had been meticulously planned over the Wagner family's 'obsession with custody'.

Sophia Wagner, now 5, is the daughter of one of the suspects and one of the victims. DeWine said there was a 'fixation' and 'obsession' regarding custody of Sophia.

George 'Billy' Wagner III, 47; his wife Angela Wagner, 48; and their two sons, George Wagner, 27, and Edward 'Jake' Wagner, 26, were all arrested on Tuesday for the murders of the Rhoden family in Ohio in 2016

Edward Wagner, Angela Wagner and George Wagner are seen here in July 2017

The Wagners, from the rural southern Ohio village of Peebles, were all charged with planning and murdering the Rhoden family who lived in the neighboring village of Piketon, 11 miles away

Jake Wagner, one of four charged Tuesday with aggravated murder, was the former longtime boyfriend of Hanna Rhoden, 19, when she was murdered in April 2016.

Sophia is their daughter. She was not with her mother on the night of the killings, but three other children, including a step-sister, were. They were all unharmed.

Sophia remains in Jake Wagner's custody having moved with her father and the rest of the family to Alaska shortly after the killings in 2017.

Hanna May Rhoden, 19, was the ex-girlfriend of one of those arrested, Edward 'Jake' Wagner. They shared custody of their daughter at the time of the massacre

The arrests are the culmination of a massive investigative effort since the seven adults and a 16-year-old boy were found dead at four different homes.

The victims were Christopher Rhoden Sr., 40; his ex-wife Dana Rhoden, 37; their three children, Clarence 'Frankie' Rhoden, 20; Christopher Rhoden Jr., 16; and Hanna Rhoden, 19; Frankie Rhoden's fiancee, Hannah Gilley, 20; an uncle, Kenneth Rhoden, 44; and a cousin, Gary Rhoden, 38.

Three children were found unharmed.

The Wagner family, who lived nearby and whose son Jake fathered Hanna May Rhoden's child, moved to Alaska after being questioned over the killings multiple times.

They took the toddler with them.

Investigators scrambling to determine who targeted the Rhoden family had conducted over 130 interviews and processed over 100 pieces of evidence and 550 tips, while getting assistance from more than 20 law enforcement agencies.

Authorities had refused to discuss many details about the slayings, saying they didn't want to tip their hand to whoever was responsible for the shootings.

Authorities in June of 2017 announced they were seeking information about the Wagners, including details on personal or business interactions and conversations that people may have had with the four.

None was named a suspect at the time. Investigators also said they had searched property in southern Ohio sold by the Wagners.

Jake Wagner was a long-time former boyfriend of Hanna Rhoden, one of the eight victims, and shared custody of their daughter at the time of the massacre.

Christopher Rhoden Sr., 40, and his ex-wife Dana Rhoden, 37, were among those killed in April 2016 in Piketon in southern Ohio

Clarence 'Frankie' Rhoden, 20, and his fiancee, Hannah Gilley, 20, were shot dead while sleeping with their child

Christopher Rhoden Sr.'s brother Kenneth Rhoden, 44, (left) and a cousin, Gary Rhoden, 38, were also shot dead.

Both Jake Wagner and Angela Wagner told the Cincinnati Enquirer they were not involved in the April 2016 killings.

Angela Wagner said in an email to the newspaper that what happened was devastating and Hanna Rhoden was like a daughter to her.

A message was left on Tuesday with John Clark, an attorney who has been representing the Wagners. Clark said a year ago that four of the Wagner family members had provided laptops, phones and DNA samples to investigators, and agreed to be interviewed about the slayings.

The Wagner family had lived in Peebles, Ohio, at the time of the killings but later moved to Alaska.

Clark said at the time that the family was being 'harassed while the real killer or killers are out there'.

Christopher Rhoden Sr. had 'a large-scale marijuana growing operation', which initially lead many to speculate that the killings were drug-related.

Investigators scrambling to determine who targeted the Rhoden family had conducted over 130 interviews and processed over 100 pieces of evidence. Pictured above is one of four murder scenes

The hearses carrying five members of the Rohden family are pictured above ahead of their funerals in April 2016

Autopsy reports suggested the murders were calculated and brutal with the coroner saying all but one of the victims was shot more than once.

Christopher Rhoden Sr. is the only victim who was believed to have been awake when they were shot.

The father-of-three sustained nine gunshot wounds in his forearm, torso and cheek.

Sharing a trailer with Christopher Sr. was his brother Gary, who was shot twice in the head and a third time in the face. His autopsy report says a 'muzzle stain' was left on his head, suggesting at one point a shot was fired while the gun was pressed against him.

Dana Rhoden was carefully shot four times around her head and a fifth time from under her chin.

She was sharing a trailer with Christopher Jr. and Hanna who were both shot in the head multiple times. Hanna was in bed with her five-day-old child at the time.

Frankie Rhoden and Hannah Gilley were also shot in the head, but their six-month-old child, who was sleeping between the couple, was spared. Hannah was shot five times in total, with one shot hitting her left eye.

Kenneth Rhoden was shot only once, with the bullet entering his right eye.

Three funerals were held for the victims.