Opinion ID: 699523
Heading Depth: 2
Heading Rank: 3

Heading: Expert Testimony and Prosecutorial Vouching

Text: 18 Robinson further asserts that the district court erred by allowing Bono and Stroud to testify that the cocaine base taken from Kennedy and the cocaine base found in the Montana Avenue house could have come from the same batch of cocaine base. Our review is for abuse of discretion. United States v. Carswell, 922 F.2d 876, 878 (D.C.Cir.1991). Although Robinson objected that the street manufacturing of cocaine base was outside Bono's expertise, Tr. 187, he did not dispute the district court's qualification of Bono as an expert in forensic chemistry, analytical chemistry. Tr. 173. Bono's conceded expertise amply permitted the district court to allow the witness to testify on the manufacturing of cocaine base. Tr. 173. The same is true of Stroud, who qualified as an expert in the street use of narcotics, Tr. 239, and expressly declined to provide an expert opinion on the frequency of purity variations in a cocaine base batch. Tr. 255. 19 Finally Robinson alleges that the prosecution improperly vouched for Bell's testimony in its closing argument by stating Well now, ladies and gentlemen, if that's a fact, if officer Bell was willing to risk his reputation and his career to come in here and perjure himself, Tr. 549, further arguing that the police were doing their jobs and had no stake in the case. Tr. 550. But Robinson had raised Officer Bell's credibility as an issue in his own closing argument and throughout the trial, arguing that Bell had been harassing Robinson and others in the Montana Avenue area. Tr. 535. The prosecutor's remarks in response to Robinson's assertions thus did not constitute improper vouching. United States v. Nnanyererugo, 39 F.3d 1205, 1209 (D.C.Cir.1994), cert. denied, --- U.S. ----, 115 S.Ct. 1969, 131 L.Ed.2d 858 (1995); see also United States v. Monaghan, 741 F.2d 1434, 1439 (D.C.Cir.1984), cert. denied, 470 U.S. 1085, 105 S.Ct. 1847, 85 L.Ed.2d 146 (1985) (The prosecution cannot be shut off from fair comment on the strength of its own witness's testimony, particularly where it is relying principally on one witness and that witness has been severely challenged by the defense.); cf. United States v. Boyd, 54 F.3d 868, 871-72 (D.C.Cir.1995) (in closing argument prosecutor erroneously vouched for police witnesses, relying on evidence outside record). 20 For the foregoing reasons, the judgment of the district court is 21 Affirmed.