Can a person with a mental disability be presented as a credible witness? Can the court actually take note of his testimony and use that as the basis for its decision? In this case I am to discuss, the two accused were charged with killing a 12-year-old girl in a cemetery. It so happened that a 28-year-old man with the mind of a five-year-old was in the vicinity and actually witnessed the crime.

So during trial, the prosecution presented this witness. The court allowed his testimony, and on the basis of which, convicted the accused. The accused’s appeal did not fare well in the Court of Appeals where the issue of competence was raised due to mental disability. When they brought the issue to the Supreme Court, it agreed with both the trial court and appellate court. It decreed:

“After a thorough evaluation of the case records, this Court resolves to dismiss the appeal for failure to sufficiently show that the Court of Appeals committed any reversible error in the assailed Decision as to warrant the exercise of this Court’s appellate jurisdiction.

Firstly, the Court of Appeals properly upheld the Regional Trial Court’s findings on the matter of Mambo’s eyewitness testimony. The Regional Trial Court rightly determined that Mambo was competent to testify. Before A.M. 19-08-15-SC amended the Revised Rules on Evidence, this Court had already categorically stated that a person with intellectual disability ‘is not, solely by this reason, ineligible from testifying in court.’

The Court expressly reinforced this stance specifically as to such persons who nevertheless could ‘convey ideas by words or signs and give sufficiently intelligent answers to questions propounded’:

In People v. Trelles, where the trial court relied heavily on the [testimony of therein private complainant, who was a person with intellectual disability,] [regardless] or her “monosyllabic responses and vacillations between lucidity and ambiguity,” this Court held: A [person with intellectual disability] is not, per se, disqualified from being a witness, her mental condition not being a vitiation of her credibility. It is now universally accepted that intellectual [disability], no matter what form it assumes, is not a valid objection to the competency of a witness so long as the latter can still give a fairly intelligent and reasonable narrative of the matter testified to.

It can not then be gainsaid that a [person with intellectual disability] can be a witness, depending on his or her ability to relate what he or she knows.

If his or her testimony is coherent, the same is admissible in court.

To be sure, modern rules on evidence have downgraded [intellectual disability] as a ground to disqualify a witness. As observed by McCormick, the remedy of excluding such a witness who may be the only person available who knows the facts, seems inept and primitive.

Our rules follow the modern trend of evidence. With the A.M. 19-08-15-SC amendments to the Revised Rules on Evidence coming into effect, the new Rule 130, Section 21(1) now simply states that ‘[all] persons who can perceive, and perceiving, can make known their perception to others, may be witnesses.’

Clearly, then, there is no basis for the defense’s insistence that ‘Mambo should have been deemed an incompetent witness from the onset.’

The accused’s appeal did not fare well in the Court of Appeals where the issue of competence was raised due to mental disability.

As the Court of Appeals ruled, the Regional Trial Court ‘did not gravely abuse its discretion in allowing Mambo to testify’: [T]he RTC conducted an independent determination of Mambo’s competenc[e] as a witness, including his ability to tell the truth, xxx.

The prosecution was able to prove with moral certainty, through the unwavering testimony of the witness Mambo Dela Cruz Delima[,] how the victim was held, assaulted, stabbed[,] and killed[,] showing the criminal intent of both accused to kill her.”

The facts and salient redacted portion of the decision are from People of the Philippines v. Jose Bragais et al. (G.R. No. 270580, 29 July 2024).