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

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.' " (People v. Ward (2005) 36 Cal.4th 186, 215.)