If you're interested in investing in Detroit you need to have boots on the ground and drive the areas. I work in Detroit and I can tell you that there are areas that are drop dead gorgeous mansions you can only dream of owning but three blocks away the neighborhood is burnt down. There is also money in Detroit, problem is most people have bad credit. If it where me and I wanted to invest in the city, I'd drive my area's to pick my locations. Hit up the local churches and talk to the pastors and preachers. they will give your leads to people who have the money and will pay on time. still, Your going to have to be on top of the property constantly. I'd also stay away from section 8. I've heard to many problems with tenants up and leaving without notice and landlord fighting with the state for the money owed.
