Paraffin Test (2024)

With respect to the paraffin test undergone by the appellant which yielded positive results for nitrates, we hold that this fact alone, uncorroborated by any other evidence, is not sufficient to establish the guilt beyond reasonable doubt of the appellant. The prosecution insists that the finding was due to the firing of the firearm which was employed to kill the victim. The defense on the other hand attributes the positive finding to the appellant’s having applied fertilizer to his plantings and manufactured fireworks thereafter. It is submitted that both these activities could produce the same positive finding: Authorities on this subject seem to support the submission of the defense.

The (Diphenylamine or Parrafin) test is not conclusive as to the presence of gunpowder because fertilizers, cosmetics, cigarettes, urine, and other nitrogenous compounds with nitrites and nitrates will give a positive reaction.^[21]
This (Diphenylamine or Parrafin) test has proved extremely unreliable in use. The only thing that it can definitely establish is the presence or absence of nitrates or nitrites on the hand. It cannot be definitely established from this test alone that the source of the nitrates or nitrites was the discharge of a firearm. The person may have handled one or more of a number of substances which give the same positive reaction for nitrates or nitrites, such as explosives, fireworks, fertilizers, Pharmaceuticals, and leguminous plants such as peas, beans, and alfalfa. A person who uses tobacco may also have nitrate or nitrite deposits on his hands since these substances are present in the products of combustion of tobacco. As a result, the usefulness of this test as evidence is very small, although it does have some investigative value.^[22]

In case of doubt, we have to rule in favor of the appellant and adopt the interpretation consistent with his innocence. A vital finding of fact which negates the prosecution’s insistence on the guilt of the accused is that no firearm was presented by the prosecution to corroborate its claim that Mendoza was the person who had fired the gun that felled Felipe Hernandez.

PEOPLE OF THE PHILIPPINES,appellee,
vs.
CORNELIO CAJUMOCAN,appellant.

We note at this point that while the positive finding of gunpowder residue does not conclusively show that the petitioner indeed fired a gun, the finding nevertheless serves to corroborate the prosecution eyewitnesses’ testimony that the petitioner shot the victim. Furthermore, while it is true that cigarettes, fertilizers,urineor even a match may leave traces of nitrates, experts confirm that these traces areminimaland may be washed off with tap water, unlike the evidence nitrates left behind by gunpowder.

LETICIA I. KUMMER, PETITIONER, VS. PEOPLE OF THE PHILIPPINES, RESPONDENT.

G.R. No. 174461, September 11, 2013 ]

The ability to determine whether an individual has fired a firearm is of great significance in the investigation of both homicides and suicides. Thus, over the years a number of tests have been developed in an attempt to fill this need The first of such tests was the “paraffintest” also known as the “Dermal Nitrate” or “diphenylaminetest.” In thistest, the hands were coated with a layer ofparaffin. After cooling, the casts were removed and treated with an acid solution of diphenylamine, a reagent used to detect nitrates and nitrites that originate from gunpowder and may be deposited on the skin after firing a weapon. A positivetestwas indicated by the presence of blue flecks in theparaffin. Although thistestmay give positive results on the hands of individuals who fired weapons, it also gives positive results on the hands of individuals who have not fired weapons because of the widespread distribution of nitrates and nitrites in our environment.^[9]Thus, nitrates can also be found in many other materials, including cigarette smoke,urine, fertilizers, and other kinds of chemicals such as oxidizing agents.^[10]

To be sure, negative gunshot residue results do not conclusively mean that a subject did not fire a gun, and positive gunshot residue results do not prove someone fired a gun either. Thus, thistestfor residue on skin has been challenged in the courts and fell into disfavor and disuse because of the ambiguity in conclusions whether an individual fired a weapon or not.^[11]

In our jurisprudence, we have consistently held thatparaffintests are inconclusive, to wit:”. . . Scientific experts concur in the view that theparaffintesthas . . . proved extremely unreliable in use. The only thing that it can deliberately establish is the presence or absence of nitrates or nitrites on the hand. It cannot be established from thistestalone that the source of the nitrates or nitrites was the discharge of a firearm. The person may have handled one or more of a number of substances which give the same positive reaction for nitrates or nitrites, such as explosives, fireworks, fertilizers, pharmaceuticals, and leguminous plants such as peas, beans and alfalfa. A person who uses tobacco may also have nitrate or nitrite deposit on his hands since these substances are present in the products of combustion of tobacco.”^[12]

PEOPLE OF THE PHILIPPINES, PLAINTIFF-APPELLEE, VS. MARIANO PASCUA, JR. @ “PEDRO” & JOHN DOES, ACCUSED.

G.R. No. 130963, November 27, 2001 ]

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