First check the documents of the seller, whether he really is who they claim to be. A passport can be faked, so ask to see other documentsproving the identity, for example, health insurance or driver's license.
If the person registered in the apartment, then look at the registration page in the passport. In other documents also must be set to the address of the residence. The ideal would be if you go to the passport office and check personally. Be sure to talk to your neighbors.
If the person does not inspire you trust, or similar person who abuse alcohol, don't be afraid to ask him for a certificate stating that he is not on the account in a psychoneurological clinic. This will help you avoid possible lawsuits challenging the contract of purchase and sale, as at the time of conclusion of the contract the person was incapacitated.
Check the documents on the property right: the act on privatization, the contract of sale, certificate of ownership. In any case can not contact the copies and even those that are notarized. All documentsinvolved in the operation of sale must be presented in original form.
If the person is not the sole heir or the owner of the apartment, there must be consent of all owners, which is notarized. If the apartment is registered the child, then there should be permit from the Board of Trustees. In case if the apartment is inherited, find out if there are any more heirs, claiming the apartment. If the sale is by power of attorney, you must meet with the master. Go to the housing office, suddenly in the apartment at the time of sale someone else spelled out.
Make a request to the unified register of court decisions to find out whether this apartment is the subject of litigation. If the case is confirmed, then consult with the expert, there is a risk of resuming the case on newly discovered facts. Check the previous transaction related to this apartment. Specialists have the opinion that if the apartment is sold for the first time in the last three years, this transaction is considered to be safe, but the risk remains.