The 9-year-old Michigan girl taunted on Facebook by neighbors while she suffered from a terminal disease died Wednesday, according to WXYZ-TV.
Back in late 2010, 33-year-old Jennifer Petkov, who lived on the same block as Kathleen's family, allegedly began cyberbullying the little girl.
On a Facebook page under Petkov's name, there were images of Kathleen's mother, Laura, in the arms of the Grim Reaper and Kathleen above a set of crossbones. Neighbors also accused Petkov and her husband Scott of building a coffin, putting it on their truck and driving past the Edward home, honking the horn.
When asked by a reporter from Detroit television station WJBK why she posted the photos, Jennifer Petkov said it was for "personal satisfaction" and because it upset the child's grandmother. At the time, the two were locked in a longstanding feud that Kathleen's grandmother said involved Petkov's being upset because she believed her children weren't invited to a birthday party the grandmother threw.
The little girl's plight attracted attention around the world, and social media pages attacking Petkov sprang up online. The Petkovs also allegedly received death threats and had eggs thrown at their house. Jennifer Petkov later apologized to the Edward family, telling a local newspaper her actions were "ignorant."
In February 2011, the news web site MLive.com reported that Petkov pleaded guilty to assaulting another neighbor and as part of a plea deal, agreed to serve 18 months probation and was ordered to move out of her house and stay away from the neighbor as well as undergo a psychological evaluation.
At the time the news of the bullying broke, mental health experts told ABCNews.com that without knowing more about the Petkovs, it's difficult to say exactly why the couple behaved the way they did. The experts believe there could be a variety of reasons for their behavior, including poor conflict resolution skills, a lack of moral development and the desire to bully.
"This is probably the most extreme case [of cyber-bullying] I've ever heard of," said Cheryl Dellasega, author and professor of humanities at Penn State University College of Medicine in Hershey, Penn. "It's another way that people can say things that are really cruel that they wouldn't say to somebody's face. They're angry, resentful and jealous and put it up on Facebook knowing that the other person will see it."
Peter Sheras, a clinical psychologist and professor at the University of Virginia as well as an author of several books on bullying, said if Petkov did exhibit that type of behavior, it's more indicative of an inability to settle disputes.
"We don't have very good skills at managing conflict," said Sheras. "We don't have enough mechanisms for socializing people into civility."
Dr. Ken Robbins, clinical professor of psychiatry at the University of Wisconsin, said, "Some people don't make it to full moral development and don't learn about empathy or feel guilt or remorse."
He also characterized the behavior as bullying, and said adults who are bullies lash out at others for the same reason children who are bullies do.
"It's a way to feel like they're taking control of a situation, acquiring power by demeaning others and by making others feel humiliated."