You may be having plans out of your imagination to protect your interests, for example the step what you have suggested in your post.
Whereas the law is different.
The procedure to buy a property is by entering into a registered sale agreement, pay an advance amount towards part payment of the sale consideration amount, pay the balance amount at the time of registration of the executed sale deed.
If yo0u suspect the integrity of the vendor, then do not enter into sale agreement at all, go for the purchase directly by making the entire amount ready for passing consideration towards execution of registered sale deed without entering into an agreement first.
Or, you may decide not to buy this property if you suspect foul play.
Take an opinion from a local lawyer on all such further issues.