It is a common scenario in Philippine real estate: a piece of land is sold through a Deed of Absolute Sale, the buyer takes possession, but for one reason or another, the title is never formally transferred. Decades pass, the seller dies, and suddenly the seller's heirs contest the sale, claiming their parent’s signature on the old document is a forgery.

When the primary signatory is no longer around to confirm or deny their signature, Philippine law and jurisprudence provide specific mechanisms, presumptions, and rules of evidence to resolve the dispute.

1. The Legal Status of the Deed: Public vs. Private Document

The ease of proving a signature depends heavily on whether the old Deed of Sale was notarized.

Notarized Deeds (Public Documents)

If the Deed of Sale was notarized at the time of execution, it is considered a public document under the Rules of Court.

The Presumption: A notarized document enjoys the presumption of regularity and authenticity. It is admissible in evidence without further proof of its due execution.
The Burden of Proof: The burden falls entirely on the heirs or the party alleging forgery. To overturn a notarized deed, the evidence of forgery must be clear, convincing, and more than merely preponderant. A mere denial by the heirs will not suffice.

Unnotarized Deeds (Private Documents)

If the deed was executed via a private writing (not notarized), it is a private document. Before it can be admitted into evidence, its due execution and authenticity must be proven. This means the buyer must actively prove the signature is genuine.

2. The "Ancient Document" Rule: A Shield for Old Deeds

If the Deed of Sale is exceptionally old, the buyer may not need to prove the signature's authenticity at all. Under Rule 132, Section 21 of the Revised Rules on Evidence, a private document is covered by the Ancient Document Rule and is self-authenticating if it meets three strict criteria:

Age: The document must be more than 30 years old.
Proper Custody: It is produced from a custody where it would naturally be found if genuine (e.g., in the possession of the buyer who has been living on the land).
Unblemished Condition: It is unblemished by any alterations or circumstances of suspicion.

Legal Impact: If these three elements are met, the law presumes the document is genuine, and no further proof of the deceased seller's signature is required. The burden shifts to the challengers to prove otherwise.

3. How to Prove a Deceased Seller's Signature

If the document is less than 30 years old and unnotarized, or if the presumption of an ancient/public document is successfully challenged, the signature must be verified. Rule 132, Section 22 outlines how the genuineness of a person's handwriting and signature may be proved:

By Witness Testimony: Anyone who actually saw the deceased seller sign the Deed of Sale can testify to its authenticity.
By Familiarity: A witness who is familiar with the deceased seller's handwriting can testify. This familiarity must be established by showing the witness has seen the person write, or has seen documents purporting to be written by the person in the ordinary course of business.
By Comparison (Specimen Signatures): The court can compare the contested signature on the Deed of Sale with standard/specimen signatures known to be genuine.

Sourcing Genuine Specimen Signatures

To conduct a proper comparison, the party proving the sale must secure official, undisputed documents signed by the seller during their lifetime. Ideal sources include:

Voter registration records (COMELEC)
Marriage certificates or birth certificates of children
Old passports, SSS, or GSIS records
Land tax declarations or older, uncontested titles/deeds

4. The Role of Handwriting Experts (NBI and PNP)

While parties often resort to handwriting experts from the National Bureau of Investigation (NBI) or the Philippine National Police (PNP) Crime Laboratory, Philippine jurisprudence emphasizes that expert testimony is not mandatory, nor is it strictly binding on courts.

The Supreme Court has consistently ruled that handwriting experts are helpful, but the judge is the ultimate arbiter. A judge can independently examine and compare the strokes, flourishes, and pressure points of the signatures to determine forgery or authenticity.

5. Testifying on Transactions with a Deceased Person

A critical procedural update involves who can testify. Historically, the Dead Man’s Statute (Surviving Party Rule) prohibited a regular buyer from testifying about their transactions with a deceased seller because the deceased could no longer refute the claim.

However, under the 2019 Amendments to the Revised Rules on Evidence (which took effect in 2020), the Dead Man’s Statute was explicitly deleted.

The Modern Rule: The surviving buyer is now legally allowed to testify about the oral and written agreements they had with the deceased seller.
The Caveat: While the testimony is admissible, courts still view self-serving oral testimonies with caution. Thus, corroborating documentary evidence (like the signature on the deed or receipts of payment) remains vital.

6. Remedial Steps for Buyers Holding an Old Deed

If you possess an old Deed of Sale signed by a seller who has passed away, and the heirs are uncooperative, the following legal remedies are available to perfect your title:

Action for Specific Performance: If the deed is valid but unnotarized, the buyer can sue the heirs to compel them to execute a formal, registrable public document. Obligations arising from contracts are transmissible to the heirs up to the value of their inheritance.
Quieting of Title: If the heirs cast doubt on your ownership by claiming the deed is forged, an Action to Quiet Title can be filed to remove the cloud or doubt over your property right.
Presentment of Corroborating Evidence: Always gather secondary evidence of the sale, such as receipts of payment, proof of continuous possession, and the payment of real property taxes under your name. Under Philippine equity, long-term open possession strongly supports the validity of an underlying sale.