Should I buy a rental property that already has tenant? Risky?

[Edward Shen]

Hi everyone, I am currently looking at buying a property to rent out. I was initially thinking of possibly getting a property that need renovation, fix it up, and then rent it out. However, while I was looking on Zillow. I found a property that is being sold at a fair price that was specified that there are already a tenant that will like to stay at the rental. The price is about $60k for the property, the property seems to be in good shape from the pictures. The only thing is that the tenant is paying $800, in which seems to be below average about 100-200$ according to rentometer.com. The only thing is that I am unsure of are: what might be the risk? It seems that even though it is below average rent pricing, the cost of the property compare to the payment of rental, it seem pretty good. Therefore, why will someone want to sell it? Is there a catch? Please help. Thank you.