LOS ANGELES, Calif. - A U.S. citizen who was illegally detained and twice deported to Mexico said immigration officials refused to believe his claim of citizenship, even when his mother traveled to the border to show Immigration and Customs Enforcement agents his birth certificate.

Guillermo Olivares of south Los Angeles was being held in a detention facility in San Diego earlier this month until an attorney for the American Civil Liberties Union of Southern California presented his birth certificate along with school and vaccination records to immigration authorities. Olivares was released later that same day.

'They didn't believe me,' a frustrated Olivares said of his numerous encounters with immigration officials. 'It seemed like there was nothing else I could do.'

Olivares' mother, Eduvina Romero, echoed his story, explaining that she and her son repeatedly showed border immigration officials his birth certificate, to no avail. 'They would never listen. It felt so unfair that they could simply disbelieve my son's citizenship without giving us any chance to prove that what we said was true. It made me panicked and anxious,' she said. 'I just wanted my son to be able to come home.'

Olivares is not the first U.S. citizen to be illegally deported. Pedro Guzman of Lancaster was deported to Mexico in 2007 and spent nearly three months lost in that country while family members desperately searched for him. In addition, Sens. Edward Kennedy of Massachusetts and Robert Menendez of New Jersey recently sponsored the Protect Citizens and Residents from Unlawful Raids and Detention Act (S. 3594), to protect the rights of U.S. citizens and legal residents who get caught up in immigration raids.

Olivares was not picked up in such a raid, but the egregious violation of his rights as an American citizen dramatically demonstrates the same problem: that federal Immigration and Customs Enforcement (ICE) officials routinely disregard the Constitution when enforcing federal immigration law.

'If ever there was evidence of the fundamental flaws in our immigration system, it is the fact that a U.S. citizen was deported twice and denied entry into the United States on numerous occasions without any due process of law,' said Jennie Pasquarella, staff attorney for the ACLU/SC. 'ICE officials repeatedly ignored his certified birth certificate, which they could easily have corroborated, and instead simply refused to believe him. It is inconceivable that this would have happened were he not Latino.'

Olivares was born in the Los Angeles area, and had never lived outside the United States until he was forced to live in Mexico after ICE deported him in 2007 and refused to allow him to re-enter. But his ordeal began in 2000, when border agents questioned the veracity of his birth certificate and whether it belonged to him when he was returning into the United States at the Tijuana border crossing. The agents refused to let him enter his own country. A week later, however, Olivares' mother met him at the border crossing with a certified copy of his birth certificate, and Olivares and his mother re-entered the United States without incident.

In 2007, while Olivares was serving time in state prison, agents from the Department of Homeland Security approached him and told him he was a Mexican citizen and would be deported. Olivares insisted that he was a U.S. citizen, but eventually - not fully understanding his rights as an American citizen - he was coerced into signing papers that were never explained to him and was deported to Mexico.

He then attempted to cross back into the United States, but border guards refused to let him enter. He felt he had no choice other than to live for a time with his mother's family in Jalisco. But in June 2008, upon learning that his father in Los Angeles was gravely ill, Olivares again tried to cross the border legally, presenting a certified copy of his birth certificate. After being rebuffed, he crossed illegally, but was picked up by the U.S. Border Patrol. On September 2, 2008, he was deported for a second time to Mexico, on the day his father died.

In September, Olivares - accompanied by his mother -- tried yet again to re-enter the United States legally from Tijuana. Once again, immigration officials rejected his birth certificate. However, this time he refused to sign his name to the papers foisted upon him and demanded to see a judge. As a result, ICE put Olivares in removal proceedings and detained him at the Otay Mesa Immigration Detention facility in San Diego. The family then contacted the Coalition for Human Immigrants' Rights of Los Angeles, which in turn contacted the ACLU/SC. On October 9, ACLU/SC staff attorney Jennie Pasquarella advised ICE that it had no authority to detain Olivares because he was a U.S. citizen, and presented his birth certificate and other documentation demonstrating his citizenship. He was released later that day.

'There's something fundamentally wrong with the system if border guards can effectively deprive you of your citizenship by simply disregarding a valid birth certificate,' said Pasquarella. 'ICE officials obviously used race and ethnicity as a basis for enforcing our nation's immigration laws, rather than taking a few minutes to verify Mr. Olivares' legal status.'

A hearing in federal immigration court in Olivares' case has been set for Jan. 6, 2009, at which Olivares will seek to terminate the removal proceedings against him.