Arguably the poorest US state, West Virginia, has a typical murder rate of around 3 to 4 per year per 100k.
Vietnam has been extraordinarily poor for the last half century, only recently beginning to climb economically. Its murder rate is typically 1 to 1.5 or so.
Per capita income probably only has a correlation in regards to the resources you have available to deal with crime problems if such presently exist, rather than being the defining characteristic of whether eg murder will be prevalent in a nation.
