Yes, and they typically do. Even if the prior conduct was unreported (they never called 911) and didn’t result in a conviction or an arrest, the prosecution can still use it against the defendant. This type of information often comes directly from the victim of the crime, who might say something like “This is not the first time that this has happened to me. My spouse has hit me in the past. I just didn’t call the police because I was scared and I was being threatened.” The underlying assumption is that the typical response of victims in these types of domestic violence situations is to not report the conduct out of fear, love, or perceived necessity. However, unreported conduct from the past can still be used.