This combination of undated photos provided by the Ohio Attorney General's office show Rita Newcomb, left, and Fredericka Wagner. Picture: Ohio Attorney General's office via AP

Cincinnati — Two women who are the mothers of two suspects in the massacre of a family, and the grandmothers of the other two, pleaded not guilty Thursday to misleading investigators of the crime, which went without any arrests for more than two years.

Authorities, meanwhile, braced for a long, complex and expensive court case that has already taken a financial toll on the small, rural county where eight members of the Rhoden family - seven adults and a teenage boy - were found shot in the head at four rural Ohio homes in April 2016.

Fredericka Wagner, 76, and Rita Newcomb, 65, face felony charges of obstructing justice and perjury for impeding an investigation; Newcomb is also charged with forgery. A county judge set bond at $100 000 (around R1.4 million) for Wagner and $50 000 (around R708 000) for Rita Newcomb. If released, both would be placed on house arrest and monitored by electronic anklets.

An attorney for the family has said they will be vindicated.

Fredericka Wagner is the mother of Billy Wagner. Rita Newcomb is the mother of Angela Wagner.

Newcomb's attorney, Franklin Gerlach, portrayed his client as a grandmother living on Social Security. Wagner's attorney, James Owen, said Thursday that his client "lived as close to the cross as anyone can" and taught Sunday school for decades.

Attorney General Mike DeWine has given scant detail about why the victims were killed, other than saying the custody of a young child played a role.

Fredericka Wagner, 76, of Lucasville, Ohio, covers her face as she walks into the Pike County Courthouse for her arraignment in Piketon, Ohio. Picture: Meg Vogel/The Cincinnati Enquirer via AP

One of the suspects, Edward "Jake" Wagner, was the longtime former boyfriend of 19-year-old Hanna Rhoden, one of the victims, and shared custody of their daughter. Family members say the girl, now 4, is in state custody.

A death penalty case this size could be "extraordinarily complicated and difficult," said Michael Benza, a Case Western Reserve University law professor who has also represented death penalty defendants.

Ohio law requires defendants in capital cases to have two lawyers, both certified in handling death penalty charges. Each side must also hire numerous investigators and expert witnesses, who could cover everything from blood patterns to ballistics in each killing.

Fredericka Wagner, 76, of Lucasville, Ohio, walks into the Pike County Courthouse for her arraignment. Picture: Meg Vogel/The Cincinnati Enquirer via AP

While prosecutors might favour a single trial, it's likely defence attorneys will push for separate trials for each defendant, Benza said, adding to the burden on the county. And many trials could swamp a small court like the one in Pike County, where the two common pleas judges already handle numerous other cases. The cost over the years, including appeals, could run into the millions, Benza said.

"Capital cases are already a tremendous use of resources, but now you've added four, with eight victims," Benza said Thursday. "It's not just times four, it's an exponential increase in cost, in time, in personnel."

State Supreme Court rules allow judges to ask that an extra judge is appointed temporarily in situations when courts are "overburdened," though no request has been made yet in Pike County.

The victims of the 2016 killings were 40-year-old Christopher Rhoden Sr.; his ex-wife, 37-year-old Dana Rhoden; their three children, 20-year-old Clarence "Frankie" Rhoden, 16-year-old Christopher Jr., and 19-year-old Hanna; Clarence Rhoden's fiancée, 20-year-old Hannah Gilley; Christopher Rhoden Sr.'s brother, 44-year-old Kenneth Rhoden; and a cousin, 38-year-old Gary Rhoden.