Murderers who kill intimate partners and family members have a significantly different psychological and forensic profile from those who kill people they do not know, researchers found.
The new knowledge about murderers who commit what is called spontaneous domestic homicide - emotionally driven crimes that are not premeditated - could enable early intervention to prevent the homicide, they said.
"The killers in this group are very similar to each other and different from men who commit nondomestic murders, which are often premeditated," said lead author Robert Hanlon, director of the forensic psychology research lab at Northwestern University Feinberg School of Medicine.
The study on spontaneous domestic homicides found these killers have more severe mental illness (particularly psychotic disorders), few previous felony convictions, are less intelligent and have more cognitive impairment.
"These crimes are often preventable if family members are more informed about the potential danger from having someone who is severely mentally ill in the home and who may have shown violent tendencies in the past," Hanlon said.
"The fact is the husband or son may very well harm the wife or mother," Hanlon said.
These murders are not a premeditated, strategic type of killing, he noted.
"These murders are in the heat of passion and generally involve drugs or alcohol and often are driven by jealousy or revenge following a separation or a split," Hanlon said.
Intimate partners and family members need to notify the authorities that they are concerned about potential harm and remove themselves from the situation, he added.
