A long-running Bakersfield homicide case took a major turn Thursday when the FBI announced that the guardians of a three-year-old girl found slain in a Southwest home in 2010 have been arrested in Mexico.

FBI spokeswoman Gina Swankie confirmed Thursday night that Alberto and Carla Garcia are in custody in Mexico, a few months short of two years after Serenity Julia Gandara was found dead at the couple's home.

Bakersfield police were sent to the Garcia's home on July 18, 2010 after the Carla called her sister and told her to go to the house. Police found Serenity's body and her 4-year-old brother Isaiah Gandara in the abandoned home in the 5900 block of Summer Country Drive.

Investigators said the couple left sometime in the night, taking their 5-year-old daughter Crystal Garcia, 4-year-old Alberto Garcia Jr. and Carla's 9-year-old son Carlos Sobalvarro Jr. from a previous marriage with them. The Garcias were both 26 when they fled with the children in the family's white 1997 Ford Expedition, according to police.

The day after Garcias vanished, police announced that they believed the family was in Mexico.

Murder and child endangerment warrants were issued for the couple. The Kern County coroner's officer determined blunt force trauma injuries killed Serenity and ruled her death a homicide.

The Garcias were in the process of adopting Serenity and Isaiah, the children of Alberto's sister Yesenia Garcia. The children were removed from Yesenia's custody by Child Protective Services because of her past reported drug problems. Isaiah was placed in protective custody after his sister's death.

At Serenity's funeral, Yesenia said she had seen her daughter twice a week when she was in CPS's care but that Carla stopped the visits when she and Alberto took in Serenity.

Shortly after Serenity's death, Alberto's mother Maria Garcia told The Californian that she hadn't been allowed to see the children for the last 14 months after she saw Carla hit Isaiah with a shoe hard enough to leave a mark on his leg.

"I told her, 'You cannot do that,' " Maria said. "'They are not your children.'"

Maria said she reported the shoe incident to CPS months after it happened. Maria said she repeatedly asked CPS to check on the children because she couldn't.

Though she no longer saw her grandchildren in person, Maria said she talked to Alberto regularly and that he always told her the kids were fine. He said the same thing the day before he and his wife fled the country.

The day Serenity was found dead, neighbors told a reporter that Alberto was an unemployed mechanic and Carla was the family's breadwinner with her housekeeping business.

While neighbors' accounts painted the family as a happy bunch, police said Serenity and Isaiah had "scars and marks in various stages of healing, including recent injuries."

The FBI said it is assisting the Bakersfield Police Department in bringing the Garcias back. The Garcias are charged with first degree murder and willful cruelty to a child, according to Kern County Superior Court Records.

Swankie said further information about how the couple was found would have to come from the police department.

Bakersfield Police Department Sgt. Mary DeGeare said Thursday night that she did not have access to information about how the couple was apprehended.