SAN DIEGO -- Seven months into the year and already 139 underage girls have been reported missing in San Diego.

Some are runaways, some return home on their own.

Others are lured to a place difficult even for police to track, where they are stuck in a life far different from their dreams.

From there, even one rescue is a success.

Nearly 2 months after her 14-year-old daughter disappeared, one lucky mother got word her daughter was found in the interior of Mexico.

“My heart is happy, happy,” said Francisca Guabarrama.

10News waited with Guabarrama, at the International Border until the wee hours of the morning.

The transfer was being coordinated by an international rescue agency.

Finally, word came to Guabarrama that her daughter was clearing customs.

Her daughter beat the odds and made it back.

Law enforcement sources told 10News the girl met an older boy on My-Space, who was believed to be linked to a National City gang.

“Some of these girls leave with people we suspect to be gang members that do have ties to organized crime in Mexico,” said National City Police Detective, Antonio Ybarra.

The two agreed to meet at Kimball Park on June 2, 2009.

Like many other cases, the girl ended up in Mexico, alone and unable to get home, police said.

None of several other girls believed to be in Mexico has been found.

“The farther you go into the interior of Mexico, the more difficult that becomes,” said National City Police Sergeant, Mike Harlan.

What's happening to them is frightening.

“We have some cases that are active where's there's prostitution, human trafficking. They're used for transporting narcotics and we're not able to get to them,” said Ybarra.

The Guabarrama’s happy ending almost didn't happen.

“They went into hiding,” said former San Diego District Attorney Investigator, Juan Briones, who is now with the Bilateral Safety Corridor Coalition.

He was sent to Guadalajara because he has almost 20 years experience with international missing person's cases.

He went down to bring Guabarrama back home.

“The victim somehow feels powerless and that they need help,” Briones said.

Briones said he threatened criminal charges against the men living in the home with the young girl and they eventually released her.

“It’s difficult to get to these kids to understand,” Ybarra said, “that where you and I can go to any pay phone and dial 9-1-1 and get police service, it does not work that way over there.”

While one girl has been given another chance, many others remain in danger south of the border.

Law enforcement sources say the cooperation between Mexican and U.S. law enforcement agencies has improved in recent years, but it still takes time to get a minor home.

“If a young girl has already slipped into the hands of a cartel to be sold into prostitution and drug running, it's, at the very least, extremely difficult to ever reach her,” Briones said.