Is a prosecutor permitted to vouch for the credibility of a witness?

Moreover, in context, the comment did not constitute improper vouching. "A prosecutor is prohibited from vouching for the credibility of witnesses or otherwise bolstering the veracity of their testimony by referring to evidence outside the record. [Citations.] Nor is a prosecutor permitted to place the prestige of [his or her] office behind a witness by offering the impression that [he or she] has taken steps to assure a witness's truthfulness at trial. [Citation.] However, so long as a prosecutor's assurances regarding the apparent honesty or reliability of prosecution witnesses are based on the 'facts of [the] record and the inferences reasonably drawn therefrom, rather than any purported personal knowledge or belief,' [his or her] comments cannot be characterized as improper vouching. [Citations.]" (People v. Frye (1998) 18 Cal.4th 894, 971.)