PHOENIX (AP) -- An Arizona woman is accused of killing her daughter on Christmas Day and trying to fatally stab her ex-husband and poison her other three children over a custody dispute.
Police say a California man apparently killed his wife and their two children before turning the gun on himself; a suburban Phoenix father killed himself and his two young daughters at their home; and a 38-year-old woman in New Mexico was charged with kicking her child to death.
All the violence occurred around the holidays.
"There does seem to be a tendency for homicide rates involving family members to increase somewhat during December and the holiday period," said James Alan Fox, a criminologist at Northeastern University.
Many of the killings have common themes - custody disputes, drug abuse, mental illness and divorce - that can erupt as relatives gather for celebrations.
In colder climates, increases in family violence can be linked, in part, to spending more time together indoors in close quarters, leading to confrontations that otherwise might not have ended in tragic consequences, Fox said.
Numerous factors come into play simply because "during the holiday season, families tend to congregate more than other times of the year which leads to opportunities for conflict to get out of control," he added.
The holiday season also can exacerbate depression for people surrounded by others feeling joy.
"It's a happy time for some but that can mean sad times for others who aren't sharing in that joy," Fox said.
In Casa Grande, south of Phoenix, a 35-year-old woman was being held on suspicion of one count of first-degree murder and four counts of attempted murder in the Christmas Day attack.
Police say she lured her ex-husband to her apartment then stabbed him repeatedly before he was able to flee and call 911. She didn't want her ex-husband to have custody of their children after their recently finalized divorce, police said.
In Fontana, Calif., east of Los Angeles, authorities haven't released a possible motive after the man apparently killed his wife and their two children on Dec. 30. Relatives told authorities the couple had been going through a separation.
A suburban Phoenix father who police say fatally shot his two young daughters before killing himself on New Year's Day, also was going through divorce proceedings.
On New Year's Eve in Phoenix, a 51-year-old man was arrested on suspicion of murder after police say he killed his 13-year-old son with an ax. Authorities said he believed his son was a demon and was going to eat him.
"The holidays bring up all sorts of issues in families in which there is already discord," Fox said. "Overall, homicides among intimate partners and family members are lower than 20 to 30 years ago. So things are better, but this time of year we often see more cases like these."
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