In Matter of Angel A., 92 NY2d 430 [1998])., the Court of Appeals held that a juvenile delinquency petition, which accused a youth of criminal sale and possession of a controlled substance, is legally sufficient where the petition was accompanied only by the supporting deposition of an undercover officer who stated that the youth had sold him four glassines containing heroin, and further stating that the presence of the controlled substance was established by a "NIK" field test, the same test as that used in the present case. Citing its decision in People v. Swamp, 84 NY2d 725 [1995]), the Court of Appeals stated that "ultimately, the Court [in Swamp] held that an uncontradicted field test result could provide legally sufficient evidence of the presence of a drug at the Grand Jury stage, although meeting the threshold standard of legal sufficiency is not the same as establishing guilt beyond a reasonable doubt at trial." (Matter of Angel A., at 434.) The Court of Appeals in Angel A. (supra) went on to reject the petitioner's view that the undercover's assertions of expertise were conclusory and insufficient as a matter of law. The officer in that case testified that he had been trained in the identification and recognition of controlled substances and had conducted approximately 20 field tests of the same kind he conducted in that case. This was held to have been sufficient, in light of the Court's holding in Swamp (supra) that only a "reliable basis" for inferring the presence of a controlled substance was required. The Angel A. Court also rejected the petitioner's arguments related to the officer's ability to conduct a field test. "[Q]uestions regarding the ability of the officer conducting the field test go to the weight and not the sufficiency of the evidence." (Matter of Angel A., at 435.) According to the Court in Angel A., "although the reliability of scientific evidence can affect its admissibility when the reliability is challenged at trial, at the preliminary stage where a court must determine whether the evidence is legally sufficient, the presentment agency is not required to anticipate such an objection and establish the field test's general acceptance within the scientific community." (Supra, at 435.)