Police on Monday held a news conference and said they didn't know what caused 51-year-old Michael Hance to go on a shooting rampage in Copley, a small town in Ohio.
Hance killed seven people in cold blood, including an 11-year-old, before he was shot to death by police.
The Associated Press has reported that two of the seven people killed were residents of Northern Kentucky. Craig Dieter, 51, and his son Scott, 11, of Richwood, were the ones shot to death in Copley Township.
"We lost a really good kid and a very well-respected dad in the community," Thomas Hummel, principal at Gray Middle School in Boone County where Scott would have started sixth grade next week, told the AP.
Hummel told the press agency that Craig Dieter was a Boy Scout leader for his son's troop and an assistant coach for the Lego team at New Haven Elementary School, where Scott attended last year.
"I understand Scott took it upon himself to raise the flag at New Haven every morning," Hummel said. "He was a quality young man who was the victim of a horrible tragedy."
Hance was the boyfriend of 49-year-old Rebecca "Becky" Dieter, Craig's sister and Scott's aunt, police said, and the dead gunman had no known criminal record.
But neighbors told the AP that the violence, which began around 11 a.m. Sunday, was the finale of a dispute over a home that once belonged to Becky and Craig Dieter's parents.
Neighbor Carol Eshleman told the AP that Hance recently grew angry over neighbors' comments about the property.
Police said Hance went next door to the Johnsons, where he shot and killed the couple, Craig Dieter, the Johnson's 16-year-old granddaughter Autumn Johnson and an unidentified girl from Copley.