(BUTLER TOWNSHIP, Ohio) -- An Ohio man accused of fatally shooting four of his neighbors has been charged with eight counts of aggravated murder, authorities said.
Stephen Marlow, 39, was arrested in Kansas Saturday night following a multistate manhunt after four people were killed in Butler Township, a small town north of Dayton, authorities said. The victims included a married couple as well as a mother and her teenage daughter.
He has been charged with eight counts of aggravated murder -- two for each victim -- as well as four counts of aggravated burglary and having weapons under disability due to a prior felony conviction, John Porter, the police chief in Butler Township, told reporters Wednesday.
He has also been charged federally with "unlawful flight to avoid prosecution," he said.
"It is my understanding that there is potential for additional state or federal charges as this investigation continues," Porter said.
Marlow is in custody as extradition arrangements are being made, Porter said. The suspect waived his extradition rights during a court appearance on Wednesday, ABC Dayton affiliate WKEF reported.
Marlow is the primary suspect in Friday's fatal shootings. Police responding to reports of gunfire shortly before noon found the four victims suffering from gunshot wounds at "multiple crime scenes" in a residential area, the Butler Township Police Department said.
The four victims were pronounced dead at the scenes. They were identified by police as Clyde Knox, 82, Eva Knox, 78, Sarah Anderson, 41, and Kayla Anderson, 15.
Amid the manhunt, the FBI had issued a wanted poster for Marlow, whom they said should be considered "armed and dangerous."
Marlow initially was charged with four counts of aggravated murder on Friday and a state warrant was issued for his arrest, according to the FBI. A federal arrest warrant was also issued on Saturday after he was charged with unlawful flight to avoid prosecution, the FBI said.
Porter had addressed Marlow during a press conference Saturday, asking the suspect to turn himself in. "I want you to know that we want to help you. You have the ability to resolve the situation peacefully if you turn yourself into law enforcement as soon as possible," he said.
Police are still working to determine why the victims were targeted and how Marlow allegedly obtained a gun, Porter said.
Investigators are continuing to interview witnesses and look at prior contacts police had with Marlow's residence. The FBI also is investigating whether Marlow previously had sent letters to the agency, authorities said Wednesday.
The killings have shaken the community.
"This is the first violent crime in this neighborhood in recent memory," Porter said.
Hundreds gathered for a community memorial for the four victims on Monday.
"This is quite easily hell on Earth for us," Bret Anderson, husband of Sarah and father to Kayla, said during the memorial. "But I'm so grateful for the outpouring of support for us and the Knox family."
"Nothing can obviously fix what was broken," he continued. “Nothing can bring my wife and daughter back to us.”
ABC News' Matt Foster contributed to this report.