The brutal, unsolved murders of seven adults and one teen in Ohio in 2016 have the “aspects of a professional hit,” an expert said this week.

Dr. Jennifer Murray’s analysis builds on the results of an autopsy report released last week in the notorious slayings. While there have been no arrests in the case, Pike County authorities have long believed the deaths were tied to the drug trade.

All eight people shot were members of the Rhoden family.

“It has aspects of a professional hit, but I don’t think it was a cartel hit or anything like that,” Dr. Jennifer Murray, a mass killings expert and associate professor at Indiana State University, told WLWT-TV on Thursday. “They’re not usually this cleanly done. Usually, you can see right away who did it.”

Despite characterizing the murders as a drug-related crime, authorities have not named a suspect or suspects in the slayings. Attorney General Mike DeWine previously said Christopher Rhoden Sr., 40, oversaw a “large-scale marijuana grow operation.”

DeWine said last June authorities were “laser-focused” on the Wagner family, who lived near the Rhodens at the time of the killings, but later moved to Alaska, according to the Dayton Daily News.

Edward Jacob Wagner, 25, had a child with Hanna Rhoden — the 19-year-old shot twice in the head during the murders. However, neither he nor George Wagner, Angela Wagner or their son were named as suspects. Jason Kearson Clark, a lawyer for the family, told the Dayton Daily News there was no animosity between the families.

“Despite what has been said and alleged, the Wagners were on friendly terms with the Rhodens,” Clark said. “Therefore, the Wagners had no reason to wish them harm.”

The attorney said last year the family was being “harassed while the real killer or killers are out there.”

“The authorities [using the media] want the public to believe that the Wagners are responsible and have absconded,” Clark told the Cincinnati Enquirer. “If that were true, why would the Wagners have come forward on their own and agreed to give whatever limited information they had?”

While the autopsies revealed members of the Rhoden family were murdered in a sadistic manner, Murray said professionals may have helped whoever was behind the slayings.

“It’s two years later and they haven’t indicted anybody. So they did a pretty good job and I don’t think the average family typically knows how to do that. So there’s a potential they may have hired someone,” she told WLWT-TV.

Authorities suspect there were multiple attackers in the slayings and they were familiar with the area. Piketon is located 70 miles south of Columbus. The killers are believed to have worked to cover their tracks, authorities have said.

“Nobody’s seen anything like this,” Pike County Prosecutor Rob Junk said last week.