The boys, 10-year-old Charles Samuel Baines Jr. and 9-year-old Nathaniel James Baines, were allegedly taken on Wednesday by Charles Samuel Baines Sr., who has no custodial rights.
The suspect remains at large. Sheriff's officials said earlier this week that he had crossed the border into Mexico.
Baines is described as African American, 36 years old, with brown eyes and a shaved head. He is 6 feet 4 inches tall, weighs 270 pounds and has the words "Drug Cartel" tattooed on his left cheek. Investigators said he is on parole and has mental health issues.
Authorities said he was likely traveling in a stolen red four-door 2007 Kia Spectra, with California license plate number 6FMN288.
Anyone with information on the suspect's whereabouts was asked to contact Crime Stoppers at (800) 222-TIPS.