On top of the pain of that, she must also grieve the loss of her brother, whom she loved very much.
"It's been 14 years, and I still cry for what he did," she said. "My mom gets calls all the time from people who've had a murder-suicide in their family. They ask her, 'How do you continue to live?' "
It took Righter's mother several years to decide she wanted to live because she felt so guilty for what her son had done.
They lost family and friends because, Righter said, "they just couldn't deal with it, or couldn't handle watching her cry."
"We feel anger, too. We feel so much," she added. "So all we can do is tell our story, and keep telling it."
Each story is different. But mental health professionals believe there are generally two types of people whose behavior could set off alarm bells as possible attackers.
One is a "middle-aged man who is recently separated or facing pending estrangement from an intimate partner and who is depressed and has access to firearms," writes Dr. Scott Eliason. "The other is an "an older male who is the primary caregiver for a spouse who is ill or debilitated, where there is a recent onset of new illness in the male, depression and access to firearms."
That's according to a study Eliason published in the Journal of the American Academy of Psychiatry and the Law.
Sometimes, people want to kill themselves because they perceive someone has stopped loving them. The person who is perceived as withholding affection becomes a target.
"A person who is miserable about the loss of affection in their life achieves compatibility again with this person by execution," said Dr. Frank Campbell, the executive director of the Baton Rouge Crisis Intervention Center in Louisiana. He's been studying suicide for more than two decades and travels around the world to investigate suicide scenes.
"When one commits murder-suicide, they create acceptable consequences to them -- they are now with that person in a way they can control," Campbell said.
Why some kill in public
Because murder-suicide statistics aren't readily available, it's not possible to be sure how many happen in public spaces, like in Kansas City and Wyoming.
But choosing a public space, or at least doing it in front of other people, is a way to make a "major statement," said Dr. Nadine Kaslow, a professor in the Department of Psychiatry and Behavioral Sciences at Emory University in Atlanta.
"Often these are impulsive acts, too," she said. "There's just no way to know what was going through someone's head."
Public murder-suicide can be an act of communication, Campbell said. It's a way of acting out frustration and pain that cannot be conveyed in another way.
And though it's typically between two people who know each other, the label murder-suicide includes mass killings, after which the killer or killers end their lives.
Experts mention infamous Columbine High School killers Eric Harris and Dylan Klebold; or Seung-Hui Cho, the college student who killed 32 others before taking his life at Virginia Tech in 2007.
There's a lot of looking in the rear-view mirror, too. The spider web of people who are affected by a murder-suicide -- friends, family, even the community that sees it in the news -- are burdened to look for hints they might have missed.