Sorry to give you the bad news but the Bronx is not for investment properties. You will lose money. Before investing anything, you need to study the neighborhood, whether prices increase / decrease and by how much. You also need to learn how long a property stays on the market and whether there are price reductions, etc.
The fact is most of the Bronx is low income and welfare residents. Properties do not increase in value much because buyers who purchase homes here cannot afford a lot of money. In addition, many homes need major renovations and you will need cash to pay for it. There are thousands of rental buildings in the area which lowers the value of neighboring properties.
In the Bronx, the only area worth investing is Riverdale, along Pelham Parkway from Williamsbridge Rd. north to Stillwell Ave., Bedford Park and Throgs Neck. Everywhere else is a dump.