The mother at the center of a missing baby case has left Miami and is being held in the Maricopa County jail on charges of kidnapping, child abuse and custodial interference.

Elizabeth Johnson is being held on a cash-only $1.1 million bond after being extradited from Florida, police said.

Johnson was arrested in Miami on Dec. 30 after she did not show up for a custodial hearing in Phoenix, MyFoxPhoenix.com reported. Johnson had apparently driven cross-country with 8-month-old son Gabriel, the site reported. Gabriel was last seen with his mother in San Antonio. Johnson told police she gave him up to an unknown couple in Texas for adoption, according to MyFoxPhoenix.com.

After arriving in the valley, Elizabeth Johnson reportedly telephoned her grandfather, who lives in Scottsdale.

"I can't even imagine Elizabeth hurting that child or anything worse," Bob Johnson told FOX 10, according to the site.

Authorities are now naming a Scottsdale couple as "persons of interest" in the case, MyFoxPhoenix.com reported. The Smiths tell police they befriended Johnson at an airport and she offered to give her son to them to adopt — but the baby's father didn't agree.

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The Associated Press contributed to this report.