Authorities were looking for two boys who disappeared after they were last seen Friday with their mother at Los Angeles International Airport.
The boys, Sage and Isaac Cook, 14 and 9, came to Los Angeles to meet their mother Faye Ku, 41, during a custodial visit.
David Cook, the father, has full custody of the two boys and said he and Ku were in a custody dispute.
"It's a nightmare for us. We never expected to be a media story, we just expected to be a family," Cook said.
Authorities said Ku had recently submitted documents to help grant her supervised visit. Deputies now believe the documents were fake, said Sgt. Ryan Rouzon.
"The mother asked for a supervised visit in which she submitted some paperwork that appeared to be from the state of Washington. It looked legit," Sgt. Rouzon said.
Los Angeles County Sheriff's Department said it is treating the missing boys' case as a suspected "parental abduction."
Authorities said Ku, who lived in Lakewood, left her belongings, including her identification and cellphone and had no information about where she could have gone. Investigators believe it was possible Ku took the boys to China.
John Redondo, a neighbor, said he last saw cook a few weeks ago with her 2-year-old son, the boys' half brother.
"I just hope that if anyone has seen them more recently than I have, just let the police know hopefully so that they can get back to their dad safe," he said.
Anyone with information was asked to call their local authorities or the Lakewood Sheriff's Station.