The Yale study reviewed data collected from 2,500 men between 1992 and 1994. Of those, 7 percent had been involved in combat, most of them in Vietnam. Those 7 percent were responsible for 21 percent of the cases of spousal abuse reported in the survey.
Three of the killings that occurred between June 11 and July 19 were allegedly committed by soldiers who had been deployed to Afghanistan.
"Wars can directly affect a man's risk of developing a range of psychiatric problems and work and family difficulties," said Holly Prigerson, author of the study. "Our findings have important implications for the thousands of Americans now involved in military strikes against Afghanistan."
The study was published in the American Journal of Public Health in January.
Nationally about 1,400 women are killed each year by their spouses. In 2001 the military recorded six cases of spousal abuse that resulted in death, according to the Pentagon's Family Advocacy Program.
Reports of military domestic violence have actually declined for the last several years, but the Pentagon fears that does not mean abuse is down.
"We believe this reduction may be partly attributed to fears of an adverse impact on career progression and underreporting by commanders and senior noncommissioned officers," Army Vice Chief of Staff Gen. John Keane wrote in a memo to Army officers in December.
The FAP reports there were 16.5 substantiated cases of spousal abuse per 1,000 military families in 2001, which translates to 10,967 substantiated cases of physical, emotional or sexual spouse abuse.
Nationally, the numbers are lower -- 3.1 cases of violent crimes against spouses or relatives per 1,000. However, the numbers cannot be directly compared as the military counts emotional abuse in its total, and "violent crimes" in the national study include robberies.
Moreover, the average age of the military population is lower than the public at large. A 1990 study showed that all forms of marital violence occur most frequently among people under 30 years of age. In fact, that demographic has more than double the rate of spousal violence than the next age group studied, age 31 to 50.
Sgt. Alex Thompson, a spokesman for the Fayetteville Police Department, which responded to the first of the murders, believes a link should not be drawn between the crimes and the military, or the Afghan mission.
"It's disturbing, it's alarming, but I don't think there's a huge connection," he told United Press International last week.
On June 11, Sgt. 1st Class Rigoberto Nieves, a soldier in the 3rd Special Forces Group who had been back from Afghanistan just two days, shot and killed his wife and then turned the gun on himself, according to the Fayetteville police.
On June 29, Master Sgt. William Wright of the 96th Civil Affairs Battalion strangled his wife. He had been back from Afghanistan for a month, according to the Fayetteville Observer.
On July 19, Sgt. 1st Class Brandon Floyd shot his wife and then killed himself. The Fayetteville newspaper reported Floyd was a member of Delta Force, the secret anti-terrorism unit based at Fort Bragg. He returned from Afghanistan in January.
The fourth slaying can not be linked to combat duty in Afghanistan: Sgt. Cedric Ramon Griffin of the 37th Engineer Battalion was charged with stabbing his estranged wife, Marilyn and then setting her home on fire July 9. He was not deployed for the war.