More than you'd think. You're more likely to be murdered by someone you know than a stranger. iirc it's something like ~55% chance of someone you know, ~25% chance of a family member, ~45% chance of a stranger (which could be anything from drug deals gone bad to serial killers).
Yeah, this is something that frustrates me in every discussion about crime. People take a murder rate of X per hundred people and use that to argue that you have an X% chance of being murdered walking down the street. Except that's not true, because like you point out, your odds of being murdered by a rando are way lower than the murder rate as a whole!
This is exactly why the reactionary push for police in response to the murder spike in 2020 and 2021 made no sense. The issue wasn't that people were going out and murdering more — it was that they were locked down in their homes with the people most likely to murder them. You can't fix that by adding more beat cops.
That statistic could only possibly exist for solved murders. Only ~50% of murders are solved and it's much easier to solve if the victim knows the killer. This sounds like
a "looking for your keys under the street lights" scenario.
The person you are replying to is making a rational argument, not an empirical one. The premise that may be understated is "cases are more likely to be solved when the victim is known to the killer, because the amount of people who know a person is far smaller and more easily investigable than the entire general public."
Oh, I understand the premise. But one premise does not a good argument make. Maybe witnesses are less likely to cooperate if they know the murderer! Maybe this type of murder tends to happen inside homes, where there’s less likely to be evidence such as surveillance footage! Maybe it is easier but only by one or two percentage points! etc etc
You can delve into the data but but the format isn't the same for every year so it might be some work to normalize: https://www.fbi.gov/how-we-can-help-you/more-fbi-services-an...