The survivors of a deadly kidnapping in Matamoros were rescued after four days in captivity,

However, a criminal defense lawyer said there are many families who continue searching for answers in their loved one's disappearances in the Mexican state of Tamaulipas.

RELATED: Bodies of U.S. citizens killed in Matamoros returned to the states

Giovanni Barrios said he’s still looking for his son — Giovanni Barrios Jr. — who was kidnapped by members of an organized crime group in Reynosa.

Barrios Jr. is a dual American and Mexican citizen.

“I'm kind of concerned with the way they tried to find the American people missing in Mexico, because the time that I went to the U.S. government to ask for help, they didn't respond,” Barrios said.

RELATED: FBI notified of Peñitas women who disappeared after traveling to Mexico, police chief says

Barrios said he has gone to federal officials on both sides of the border, and the United Nations Office at Geneva and the International Criminal Court in the Netherlands.

His efforts haven’t been successful.

Barrios Jr. is one of the 12,600 missing people in the state of Tamaulipas alone.

“You have to look for them, they have no voice,” Barrio said.

Barrios now leads Justicia Tamaulipas, an organization that helps hundreds of other families who’s loved-ones have vanished.

RELATED: Americans found quickly, but Mexico's missing remain lost

Barrios said he hopes Mexican authorities will step up and help the people of their country like they did for the kidnapped Americans 

“They have to do the same thing they did in Matamoros with every single person missing in Mexico,” Barrio said.