Property through poa can be challenged

Hello Sir,

I request you to help me and suggest me 

I am purchasing a plot in Burari in East Delhi. 

I am purchasing this plot from Mr. Sharma (Property Builder).

Mr. Sharma will provide me a Power of Attorney in my name from the owner of the property.

I want to know if I can purchase this plot through POA. 

Will it be safe? 

Can I get my money back legally with the help of POA, if any fraud is found later or I am unable to possess the land in future.  

Thanks,
Yogesh Singh