Early stages Police believed that more than one shooter was responsible for the killings, since two of the crime scenes were within walking distance, a third located about a mile away, and the fourth about eight miles away. Investigators briefly considered the possibility of a
murder–suicide, but it was discredited as none of the victims' deaths appeared to be suicides. Attorney General DeWine stated that the killings were planned, premeditated, and "a sophisticated operation," citing the efforts taken by the shooter or shooters to cover up their tracks and remove any incriminating
forensic evidence. All of the victims were members of the Rhoden family. Surviving family members were urged by police to take precautions, and all residents of Peebles were advised to stay inside their homes the following night. An investigative task force of at least 100 members, led by the
Ohio Bureau of Criminal Identification and Investigation (BCI), was assembled. More than 251 law enforcement officials were involved in the investigation overall, and sheriffs from 25 offices across Ohio offered to provide resources to Pike County. The
Federal Bureau of Investigation and the
Drug Enforcement Administration provided technical expertise to DeWine's office. At least five search warrants were executed, and more than 50 people were interviewed in connection with the killings. Seventy-nine pieces of evidence were examined, including a
Facebook threat aimed at Christopher Rhoden Jr., which was posted before the shootings.
Discovery of cannabis and cockfighting operations On April 25, a spokesperson for DeWine's office also confirmed that
cannabis was discovered at the three crime scenes on Union Hill Road, including an indoor
grow house in which hundreds of cannabis plants were being grown, as well as chickens and equipment consistent with breeding chickens for
cockfighting. An estimated total of 200 cannabis plants were recovered from the crime scenes and are believed to have been grown for sale and not for personal use. It was not known whether the cannabis was connected to the shootings, though investigators confirmed the possibility of the involvement of a Mexican
drug cartel. Cannabis cultivation is a common occurrence in Pike County: in 2010, 22,000 cannabis plants were seized by authorities in
Latham, west of Piketon; and a major cannabis growth site was discovered by police in August 2012, with about 1,200 cannabis plants being destroyed by investigators. In both cases, police suspected connections to Mexican drug cartels. On April 26, Dana Rhoden's father, Leonard Manley, stated that the victims knew their killer(s), citing the presence of Dana's two protective dogs. There was no indication that the dogs tried to attack anyone during the shootings, and there were no signs of forced entry at any of the crime scenes. Manley, who was not involved in the shootings, also said his daughter had no involvement in the exposed cannabis operations, saying that "they are trying to drag my daughter through the mud, and I don't appreciate that."
Seizure of victims' properties On May 3, following the funerals of the last six victims, authorities towed away at least three vehicles from property belonging to the Rhoden family; a spokeswoman for Mike DeWine said they were towed "as part of the investigation". Additional vehicles were towed the next day as well. They were all dropped off at the base of operations set up by the investigative task force. As of May 12, more than 500 tips had been submitted and 128 interviews were conducted. On May 12, DeWine and Pike County Sheriff Charles Reader announced the state's intention to relocate the
mobile homes where the killings occurred to a secure location, in order to preserve evidence and protect the personal effects of the Rhoden family. Three of the homes were taken to a property in
Waverly, where the investigative task force set up their command center, while the fourth would arrive later due to complications in removing it. As of October 6, the homes were being stored in a warehouse that was once part of a chemical processing company. On November 24, dozens of family vehicles and farming equipment, which were seized and investigated earlier in May, were returned to the victims' relatives.
August 2016–January 2017 developments On August 4, during a court hearing relating to the custody of the 6-month-old and 4-day-old children left alive, Sheriff Charles Reader confirmed investigators' early suspicions that more than one shooter was involved in the killings. He also said that the two children remained in "grave danger" because of the investigation, and that the investigation was possibly the largest in the BCI's history. On August 13,
KVIA-TV incorrectly reported that two men arrested in
Hatch, New Mexico, for the shooting death of a police officer were also suspected in the Rhoden familicide. The men, in reality, were suspected of another shooting death in
Londonderry, Ross County, Ohio. DeWine and Pike County Sheriff Charles S. Reader issued a statement saying that they were unaware of a link between the case and the New Mexico arrests, that there was no evidence confirming it, and that New Mexico authorities had not contacted them about a suspected connection. KVIA later retracted the error. On August 20, DeWine announced new information regarding the investigation. He confirmed family and community members' suspicions that the perpetrators were familiar with the victims, their homes, and the surrounding area. He also announced that the
U.S. Department of Homeland Security and other federal agencies had become involved with the investigation. In addition, DeWine speculated that residents in the area have more knowledge than what they are sharing with investigators. On August 23, officials in
Kenton County, Kentucky, located about from Pike County, reported similarities between the Ohio shootings and a double homicide in Kenton County that occurred two weeks before. The victims, a well-known drug dealer and his girlfriend, were found fatally shot execution-style in their bed. The uncaught Kenton County killers, who were believed to be familiar with the victims' home, also left any children in the house unharmed. A total of 770 tips had been submitted to investigators as of September 23, according to court documents released on October 7. On September 28,
WXIX-TV reported that the Rhoden family houses, all seized by the state as part of the investigation, were not being guarded properly. A news team had spent six weeks, starting from August 14 and ending in late September, watching the warehouse. Their surveillance reportedly turned up an absence of uniformed officers guarding the building, as well as a lack of security cameras and an unlocked, open main gate. DeWine responded to the claims, calling them "ludicrous" and asserting that the evidence was preserved and is not compromised. Reacting to the report, a former prosecutor from
Hamilton County criticized the inadequate security measures and said, "Any evidence that they would pull out of that thing would be virtually useless." On October 1, DeWine said that investigators were getting leads in the case and that the state had enough physical evidence for prosecution. He also appealed to the public, explaining that there are people who know more about the shootings. On November 14, Pike County Sheriff Charles Reader issued a statement urging people with knowledge of the killings to come forward. He followed up with a second statement threatening to arrest anyone who may be obstructing the investigation, including relatives, family friends, and neighbors. Reacting to the second statement, Dana Rhoden's father, Leonard Manley, said that he "held nothing back" during the investigation. Following his reelection to the position of sheriff, Reader reiterated this belief and added that people may be scared of providing information. On January 20, 2017, DeWine, on behalf of the Ohio Victims of Crime Compensation Program, denied a request by family member David Weisel to recover lost compensation related to the massacre.
Wagner family On May 12, 2017, a
SWAT team from the
Franklin County Sheriff's Office raided a Pike County home approximately 10 miles from the site of the murders. Police originally stated they were searching for suspects in the murders; however, it was later clarified they were looking for evidence in the case and not suspects. Police also searched an
Adams County property once owned and recently sold by Edward "Jake" Wagner, an ex-boyfriend of victim Hanna Rhoden and father of her 3-year-old daughter, but not the father of her 4-day-old daughter who was unharmed during the killings. Rhoden was only 13 years old when their sexual relationship began. ==Arrests==