Unreliable evidence

We often read in the papers about suspects in shooting incidents being subjected to paraffin tests in order to determine whether they are positive or negative for powder burns. This particular case tells us about the probative value of a paraffin test. It is a case which happened in a barrio at a carinderia owned by spouses Bert and Cita. Usually, the couple not only prepares and serves the food but also entertains their customers.

Among the customers was David, a local official of the barrio, who came one evening with his friends to drink beer. They invited Bert to join them. Talks turned to politics and soon, a heated argument ensued between David and Bert. Since David had already imbibed too much beer, Bert simply advised him to go home. David grudgingly left with a dagger look at Bert. The relieved Bert sat down to rest facing Cita and leaning against the window of their carinderia. But all of a sudden, Cita saw David outside the window pointing a gun at Bert’s back. Before Cita could warn Bert, a shot rang out and Bert slumped dead in front of Cita.

Cita was questioned by the police regarding the shooting and she executed a sworn statement pointing to David as the assailant of her husband. She narrated the events leading to the shooting, emphasizing the fact that she was able to recognize David as her husband’s assailant because the area outside the window was illuminated by two light bulbs and because she had known David since childhood.

David was arrested and brought to the NBI where he was subjected to a paraffin test. The results of the test, however, showed David to be negative of powder burns. Notwithstanding this finding, David was tried and found guilty of murder. David questioned this decision claiming that he should be acquitted because the paraffin test found him negative for powder burns and, therefore, he could not have fired the gun that killed Bert. Is David correct?

No. Contrary to popular belief, a paraffin test has proved extremely unreliable in use. The only thing that it can establish is the presence or the absence of nitrates or nitrites on the hand. If the result is positive, it cannot be definitely established whether the source of the nitrates or nitrites was the discharge of a firearm because cosmetics, cigarettes, urine and other nitrogenous compounds will also give a positive reaction. On the other hand if the result is negative, it does not necessarily follow that the person being tested did not fire a gun because he might have been wearing gloves or enough time might have lapsed since the firing of the gun as to remove the nitrates.

In other words, the result of a paraffin test alone is not sufficient to establish the guilt or innocence of the accused. What is important is that there is sufficient other independent evidence which will support his conviction. In the present case, Dante’s guilt was sufficiently established by Cita’s eye-witness account of the shooting which the trial court found to be candid, categorical, consistent, and therefore, credible (People vs. Barte, G.R. No. 103211, February 28, 1994).

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