How to investigate a bad deal?

[Daniela Grozeva]

Hi there! I need an advice.  I am working with an investor from out of state. I found a property that looks really good on paper so far and he wants to buy it. My concern is that I found it on the mls and it's been on the market for 240+ days. The listing agent is an investor himself. I think there is something wrong. A bad deal if you wish. Good deals rarely go on the mls. Do you have any helpful tips on how to investigate? I called the zoning department and I am waiting to hear from someone at comprehensive planning. Thank you