What factors contribute to Massachusetts having one of the lowest per capita murder rates of any state in the country?

https://en.m.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_intentional_homicide_rate

In 2022, Massachusetts was the #5 least murderous state per capita in the country, surpassed by only Utah, New Hampshire, Iowa, and Rhode Island.

What are the reasons we are not more murderous?