In an apparent murder-suicide, police are investigating the deaths of World Wrestling Entertainment wrestler Chris Benoit, his wife and 7-year-old son at the family's home in Fayetteville, Ga.
Police have confirmed that a gun wasn't used, but the details of the deaths "are going to prove a little bizarre," Fayetteville County District Attorney Scott Ballard told the Atlanta Journal-Constitution.
The apparent killings come on the heels of several recent family murder-suicides, which criminologists and forensic psychiatrists call familicides.
Though rare, experts say, familicides tend to occur in clusters.
Benoit's wife, Nancy, 43, and son, Daniel, were each found in different rooms and are believed to have been killed days before the wrestler seemingly took his own life, according to police.
Days before the Benoit killings, independently, and on opposite sides of the country, Thomas Reilly and Kevin Morrissey each decided to kill their children and then kill themselves.
Reilly, 46, drowned his two young daughters, ages 5 and 6, in the bathtub of their Montclair, N.J., home before hanging himself from the attic rafters last Wednesday.
A week ago Monday, Morrissey, 51, shot his wife and two daughters in a parked car at a popular park near Berkeley, Calif., before turning his .357 handgun on himself.
Both crimes came after another murder-suicide earlier this month in Wisconsin. Amborosio Analco, 23, killed his two twin infant sons, their mother, their aunt and himself.
Men, experts said, are often driven to murder their families by intense feelings of shame resulting from a job loss or a perceived inability to provide for family members.
Forensic psychologists and criminologist said, however, that these murderers do not simply "snap" but usually have long histories of mental illness.
Men and women who kill their children, forensic psychologists told ABC News, tend to be severally depressed or psychotic.
Women are more likely to kill their children than men are, but men are more likely to kill both their children and their spouse, said Dr. John Bradford, head of the forensic psychiatry department at the University of Ottawa.
Police investigating the deaths of Kevin Morrissey and his family said they found a note in which the 51-year-old father of two said he was distressed over the family's financial situation.
Morissey ran a skin care clinic with his wife, Dr. Mamiko Kawai, 40. The couple's two daughters were Nikki Morrissey, 8, and Kim Morrissey, 6.
Dr. Phillip Resnick, a psychiatry professor at Case Western Reserve University, said Morrissey may have been "severely depressed and believed his family was similarly miserable. He was ending the entire family's pain."
"Money is often an issue. The man sees himself as a breadwinner and may feel like he has to take the whole family out with him," Resnick said.
Police investigating the deaths of Reilly and his children, Megan, 5, and Kelly, 6, said they didn't yet know what motivated him to drown his daughters, but that he'd recently been separated from his wife.
"There are still many unanswered questions. The couple was separated, and he had visitation rights. The wife contacted police when she couldn't reach Reilly. There was no note, and the case is still under investigation," said Roger Terry, deputy chief of the Montclair Police Department.
Local, state and federal agencies do not specifically track familicides, and discrepancies in the way the crimes are classified make getting an accurate count difficult.
Hay Carter, a professor of criminology at Florida State University, however, said these crimes -- like all mass murders -- are rare.
Carter estimated that of the approximately 16,000 murders committed annually, less than 2,000 involved family members, including parents who kill their children.
Experts said there is a greater chance that a stepparent will murder a stepchild than a biological parent will kill his own child. They also said, despite the rarity, parents are more likely to kill their children than strangers are to abduct and kill them.
Experts said that women are often motivated to kill their children for different reasons than men are.
Rather than feeling they have failed to adequately provide for their kids, women often kill their children out of a delusional sense of altruism.
Women often fail at committing suicide, said Resnick, and their crimes are therefore less likely to be classified as familicide.
"Women try three times as often to commit suicide, but men are three times more successful," he said.
Psychosis and severe depression can lead women to believe they are killing their children to end their suffering or because they believe they are demonically possessed.
"When you're psychotically depressed the whole world appears as if you're looking through dull gray glass. When you look at your children, you see them through your own suffering and emotional pain and believe they, too, are suffering. You begin to think they and you would be better off in heaven. This is an altruistic delusion. The results are horrific, but it's done in the hopes of stopping suffering," said Bradford at the University of Ottawa.
Severely psychotic women, he said, "might not see their children as suffering but see them instead as evil. They believe their child is a devil and to protect mankind they must be killed."