Diddy‘s ex-girlfriend Gina Huynh — Victim No. 3 in the federal indictment who was a no-show in court after prosecutors subpoenaed her — just went to bat for him in his bid to get out of jail pending sentencing.

In new legal docs, obtained by TMZ, Gina pens a letter to the judge in Diddy’s criminal case … supporting Diddy’s motion for bail.

Gina says she’s known Diddy for years and that she’s mostly seen him as a father, family man and business man … not a criminal.

Gina says Diddy became a better person and by the time their relationship ended he “embodied an energy of love, patience and gentleness that was markedly different from his past behavior.”

Prosecutors — and the judge — cited Diddy’s violent behavior as a reason for keeping him in jail pending his Oct. 3 sentencing … but Gina says, as far as she knows, Diddy “has not been violent for many years, and he has been committed to being a father first.”

Gina tells the judge she doesn’t think Diddy poses a danger to her or the community if he gets freed on bail … she says he should be released from jail so he can care for his family and kids who depend on him for emotional and financial support.

She also says if Diddy’s released she’s confident he will follow all conditions.