Eight-year-old Lydia Rupp was found safe in Ensenada, Mexico, and her alleged abductor is in custody, the Lyon County sheriff's office said on Friday.
Lydia disappeared one week ago along with a convicted sex offender who lived with her and her mother as a roommate.
The sheriff's office said Mexican officials are working with U.S. authorities to return Lydia to her mother in Fernley.
"I just screamed out. I was so excited. I ran into the park to tell the people I was with. I was out of breath," said mom, Carmen Bauer, who learned her daughter had been found at about 6 p.m.
Bauer said she was talking with her pastor's wife when she learned the news from Lydia's paternal grandmother who heard her granddaughter had been found on the news.
Bauer had been given a cell phone, but unfamiliar with its workings had turned down the volume and missed calls from police with the news.
"Me and my sister are driving down on Sunday. Hopefully everything will be done by then and we can bring her home," she said.
Lydia's big brother Daniel "lifted up his arms and said 'praise God'," Bauer said.
Fernando Aguero is in the custody of Mexican authorities and is awaiting extradition proceedings, the sheriff's office said.
"All I want to do right now is get the girl to mom. That's all I care about right now," Sheriff's Capt. Jeff Page said. "Aguero? I could give a (expletive) less about him. He is a predator and con man that manipulated and eyeballed a single mother. Our priority is Lydia's safety."
He said Aguero and the girl were found in a low income shelter in Ensenada after people there recognized them from flyers distributed throughout the state of Baja, Mexico.
Deputies earlier said Aguero was last seen Saturday by a relative in Tijuana, Mexico, north of Ensenada. He reportedly had been in contact with family members in California and Mexico.
In 1985, he was convicted under an alias of lewd and lascivious behavior with a child under 14 for the molestation of two female cousins under 10.
According to Lt. John Arndell of the Lyon County Sheriff's Department, Aguero served one year in a Los Angeles county jail.
Authorities said Aguero had taken the girl's birth certificate, Social Security card, photos, her clothes and even her cocker spaniel. The 47-year-old uses many aliases.
Lyon County Detectives are working with the FBI and California authorities to continue the investigation.
The sheriff's officials said they would like to thank the numerous people who provided information for the investigation.