MEMORANDUM **
Garrón Green appeals his conviction on one count of being a felon in possession of a firearm and one count of being a felon in possession of ammunition. See 18 U.S.C. *134§ 922(g)(1). The facts are known to the parties and need not be recounted here.
I
Green argues that his conviction must be reversed because the Assistant United States Attorney (“AUSA”) who tried the case improperly vouched for the credibility of government witnesses during closing arguments, while also denigrating Green’s credibility.
“As a general rule, a prosecutor may not express his opinion of the defendant’s guilt or his belief in the credibility of government witnesses.” United States v. Molina, 934 F.2d 1440, 1444 (9th Cir.1991). “Whether the witnesses have testified truthfully ... is entirely for the jury to determine; it is improper to communicate that a credibility determination has been made by the AUSA, law enforcement agents, or the court, or that the government knows whether the witness is being truthful and stands behind the veracity of the witness’s testimony.” United States v. Ortiz, 362 F.3d 1274, 1279 (9th Cir.2004).
Here, the AUSA interspersed the following assertions throughout his closing argument:
“I believe [Gloria Green] was credible what she got up there and said.... ” “I don’t think [Vincent Acosta] was truthful up here on the stand.... ”
“I don’t believe [Garrón Green] was bein’ truthful at all. At all. I found his credibility lacking completely.... I don’t believe he was truthful at all....” ‘You heard [Officer Deering’s] testimony. He’s gonna risk his job, risk his pension, risk his career for perjury, to come in here and lie? ...”
These statements constitute improper vouching because the AUSA “deliberately introduced into the case his personal opinion of the witnesses’ credibility.” United States v. Kerr, 981 F.2d 1050, 1053 (9th Cir.1992). By so doing, the AUSA usurped the jury’s role of evaluating credibility and “ignored his special obligation to avoid improper suggestions and insinuations.” Id.
The government seeks to excuse the AUSA’s impermissible statements on the ground that they were “invited” by the defense’s attempts to impeach the prosecution’s witnesses. We have held, however, that attacks on the credibility of prosecution witnesses are “legitimate tools of advocacy and [do] not, standing alone, justify such a response.” Id.
Although Green failed to object at trial to the AUSA’s vouching, this prosecutorial misconduct rises to the level of plain error. Indeed, vouching is especially problematic in cases-such as this-where the witnesses’ credibility is crucial. See United States v. Necoechea, 986 F.2d 1273, 1276 (9th Cir.1993); see also id. at 1278 (in plain error review, the court “balance[s] the seriousness of the vouching against the ... closeness of the case”). Green was not in physical possession of the rifle or ammunition at the time of his arrest, and the case’s outcome therefore hinged upon whether the jury found the prosecution’s witnesses, or those presented by the defense, to be more credible. The AUSA improperly tipped the scales in favor of the prosecution by repeatedly offering his personal opinion of the witnesses’ credibility.
II
Because the prosecutor’s improper vouching necessitates reversal, we need not address the other purported errors raised by Green.1
REVERSED.
This disposition is not appropriate for publication and may not be cited to or by the courts of this circuit except as may be provided by Ninth Circuit Rule 36-3.
. Green’s Motion for Leave to Expand the Record is denied.