@Fatih19 Here you go. Not the original study but they do link to several credible sources to make the same point. Here is the link and relevant quote:
"Two studies have found that at least 40 percent of police officer families experience domestic violence, in contrast to 10 percent of families in the general population. A third study of older and more experienced officers found a rate of 24 percent, indicating that domestic violence is two to four times more common among police families than American families in general." Cops "typically handle cases of police family violence informally, often without an official report, investigation, or even check of the victim's safety,"