Montclair, Calif. ? Prince Sagala searched for her son and daughter for 15 years, fearing she had lost them forever to the estranged husband who took them to his native Mexico.

Then one day, she typed her child’s name into Facebook on a library computer, and suddenly found herself exchanging messages with a young woman who said she was her daughter in what experts say was a rare online success in the search for missing kids online.

But the exchange wasn’t a happy reunion.

“She thought I was a stranger woman,” Sagala said, with hurt and frustration in her voice. “I wrote back and she deleted it. Then, she disappeared.”

Authorities tracked down the children, now 16 and 17, outside Orlando, Fla., and arrested their father, Faustino Fernandez Utrera, 42, on May 26. He faces kidnapping and child custody charges. Sagala is now racing to regain custody of her children before they turn 18 and she loses them to adulthood.

Florida authorities have temporarily placed the children with a nonrelative whom the pair know and set a hearing for later this month.

“This has been so traumatic for them. The father, the only person they’ve known as a parent, is now in jail. When they have children of their own, when they’re 25, 26, 27 years of age, it’s going to dawn on them what their mother lost,” Montclair police Detective Debbie Camou said. “You can’t fault them for what they feel.”

Utrera did not respond to a request for a jailhouse interview. Florida authorities did not know if he had retained an attorney.

The couple was contemplating divorce in 1995 when Sagala returned from work to find the children, then 3 and 2, gone, Camou said.

Sagala, 43, later learned through her husband’s relatives in Mexico City that he was there with the children and didn’t intend to come back, Camou said. “At that time, she was afraid to go to Mexico because he had threatened her,” she said.

Police eventually referred the investigation to the San Bernardino County District Attorney’s office, following the department’s policy, but the probe stalled.

During this time, authorities recently learned, Utrera moved to Florida with his children and got a driver’s license using a fake name. It’s unclear how long the three had been in Florida when Sagala found the Facebook page.

Meanwhile, Sagala raised two younger children she had with a man she said she married three years after Utrera fled and with whom she now lives on a quiet residential street in this city about 35 miles east of Los Angeles. It’s not clear if she ever divorced Utrera.

But she always hoped to reunite with her older children. On a visit to a neighborhood library in March, Sagala had one of her children enter her daughter’s name into Facebook and her page popped up. On March 10, she began exchanging e-mails and chatting with her daughter, and hoped to get her to reveal where she lived and re-establish a bond.

Sagala said she sent an old family photo to the teen, but her daughter broke it off, saying in an e-mail that she was happy with her family and that she’d heard bad things about her mother.