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.”

PHOTOS: Justin Bieber Snaps Pics Of Sexy Selena Gomez In Cabo

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.

The 20-year-old California woman who claims Justin Bieber is the father of her baby is moving forward with her action against the pop star, RadarOnline.com has learned.

Reports that Yeater dropped her lawsuit against Bieber and her two attorneys left the case caused a stir on Wednesday morning, but RadarOnline.com has learned Yeater’s paternity attorney is still on board and is involved in private negotiations with Bieber’s legal team.

“I did not step down and there is a legal team. It’s a new legal team. In light of death threats against my client, strategies have been reviewed...the San Diego team has been replaced by John Carlson from Los Angeles,” Jeffrey Leving, a Chicago paternity attorney who took on Yeater as a client, explained over the phone with WGNtv in Chicago.

A high-profile Chicago attorney, on the legal team of the 20-year-old California woman who's claiming Justin Bieber is the father of her 3-month-old son, told the Dr. Drew show on Tuesday that her lawyers attempted to contact Bieber's lawyers before the case was filed, and never received a response.

Yeater’s team hoped to settle the case “outside of court,” said Jeffery Leving, a lawyer known for his work as an activist for father's rights in divorce and custody cases.

Leving added he wants a “carefully supervised” DNA test to establish paternity.

PHOTOS: Top Celebrity Sex Scandals