The murder thing is really hard to tackle you have your answer from multiple viewpoints. But this what comes to mind.

Well for starters what is murder and by textbook definition its "the unlawful premeditated killing of one human being by another."

the fewer people in a given area the less of a chance of murder. but also theres unaccounted crime and reported crime. If one area has a high crime rate, then people move out, and poor uneducated people move in or can't move because of cheap restates or just don't have money to move out. Property taxes lower, poor education, very few job opportunities and most likely people will get into crime or rely on government support. Poor people don't make the best choices because of lack of education, education, lack of social services, lottery tickets, gambling, etc. The reason i bring this up, look at the New York City blackout of 1977 and the blackout of July 2019. Today, there are phones everywhere, we think the NSA is listening or watching everything. It's almost like the survivance of the self. But the 1977 New York was just a stack of issues, that i could go on about. Dating apps, uber, they're a sort of security to them. You have to put your name, license, card number they are tracking you and the driver so there is a sense of i should watch out and stay out of trouble.