Protection from Squatters

[Deanna Beadle]

I am interested in purchasing a home that has been recently known as a squatter house. 

My question is, how do I ensure squatters won't come back if I get the property? Clearly I will be doing tons of work on the house, and not living there at all. What measures would I take and how would I protect myself from this happening?

For context, the realtor had said nobody has been staying there since October (it is now June), but it is still an unsettling possibility that it could happen again.