Kelly Manchester, the former girlfriend of state Sen. Mark Montigny, testified on Friday that she is currently 30 years old, which would have made her 24 when she got her job at Probation, not 21 as a federal prosecutor claimed in his opening statement to the jury in the trial of former Probation commissioner John O’Brien.

The age discrepancy is fairly minor, but Beacon Hill officials have raised it as an indicator that federal prosecutors are willing to bend the truth to make their case more dramatic.

Assistant US Attorney Fred Wyshak said in his opening statement to the jury that they would hear evidence that Montigny helped his then 21-year-old girlfriend land a job at Probation. The reference has been repeated as fact again and again by most media outlets.

Based on Manchester’s testimony Friday, her age would have been 24 when she landed an administrative assistant’s job at the Office of Community Corrections, which is affiliated with the Probation Department, and months later a probation officer’s job at the Bristol County Probate and Family Court.

Last week, when questions were first being raised on Beacon Hill about Manchester’s age, CommonWealth asked Wyshak during a break in the trial about a possible discrepancy. He said he was exercising “literary license” in his opening statement to the jury.

Related: Montigny ex-girlfriend says senator ‘opened the door’ Wyshak said the point of his statement was that most probation officers acquire years of experience after leaving college before landing their job, while Manchester was a recent graduate of UMass Amherst (2006) with almost no job experience.

James Casey, the chief probation officer at the Bristol Probate and Family Court, testified on Friday that he was 24 or 25 when he started working at the court in 1972.

Elizabeth O’Neill LaStaiti, the former chief justice at the Bristol court, testified on Thursday that she had serious concerns about Manchester’s lack of experience at the time of her hiring, but acknowledged that she turned out to be an “excellent probation officer.”

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...