How to find out what was previously paid on a place?

When we bought our condo in the Chicago market, our real estate agent was able to find out what it was bought for by the previous owners. Does anyone know how/where to look that up for the Brooklyn market? We are interested in finding out the price for a place in the South Slope that we are considering putting an offer on.

By guest | 09/29/2007 5:37 PM