The study reaffirms a well-known connection between access to guns and abusive relationships turning deadly, at a time when intimate partner homicides are on the rise. Research has shown that women killed by their partners are more likely to be murdered with a firearm than by all other means combined, and the presence of a gun in domestic violence situations can increase the risk of homicide for women by as much as 500 percent, according to the National Domestic Violence Hotline.

Both men and women were at increased risk for domestic homicide when firearm ownership increased, the study found. “But the important caveat to that is, whereas men are victims in about three out of four typical homicides that occur, it fully reverses when we are talking about intimate partner homicide,” Dr. Kivisto said. “Women are three in four victims of intimate partner homicide.”

Other research has found an association between firearm ownership and homicide rates overall, but when Dr. Kivisto and a team of researchers parsed out the relationship between victim and offender, they found no association between the rates of gun ownership and non-domestic firearm homicides.

One possibility for the finding, the researchers hypothesized, is that perpetrators in non-domestic homicides are more likely to obtain their weapons illegally, or to buy a weapon legally shortly before the crime.

“These might not be gun owners as we tend to think of them, but gun obtainers,” Dr. Kivisto said.

The study estimated firearm ownership by state by looking at the ratio of firearm suicides to total suicides, as well as state hunting license data . The combination has been shown to have a strong correlation with older survey data on gun ownership from the Centers for Disease Control and Prevention, Dr. Kivisto said.