Mariah Yeater, the 20-year-old California woman who claims Justin Bieber sired her 5-month-old son, is holding steadfast to her story that the pop singer is the child's father.

When asked by the Chicago Sun-Times on December 14 whether or not ex-boyfriend Robbie Powell -- who was arrested November 26 on drug and burglary charges -- is the real father, Yeater replied, “Yes, I know him.”

But then insisted, "He is not the father, and he’s locked up and out of the picture.”

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Robbie Powell is reportedly the “real father” of Mariah Yeater’s baby — although she’s claiming Justin Bieber is the dad — and RadarOnline.com has exclusively learned that Robbie was arrested in San Diego over the Thanksgiving weekend.

According to the arrest report, Robbie was busted on November 26 at 11:41 p.m. for drug and burglary charges. The 23-year-old was charged with four felonies and one misdemeanor — possession of a controlled substance (methamphetamines), possession of drug paraphernalia, and three charges of commercial burglary.

Robbie is not eligible for release and currently remains in the San Diego Central Jail where he has a combined bail amount of $7,000. He has two court dates set for later this week.