Dealing with crime

[Seth C.]

I have a couple of medium sized MF deals available to me with solid demographics in terms of renting. There are a number of universities etc. nearby. However, the apartments are on the fringe of a high-crime area. They have gated parking etc. because of this, but crime still infiltrates. These properties appear to be high cash-flow properties, and one of them might even work with partial owner financing. 

My question is, when is it worth tackling crime (if ever), and is there some way to estimate financial impact? Depending on lease terms it may take 1-2 years to clean up the apartments themselves, but it is impossible to clean up the entire area. These apartments are 90%+ full right now but can be value-add as well. C property in B- to B neighborhood bordering on C- neighborhood, all taken in local terms--it is a high-crime city.