While in jail for a misdemeanor, a US citizen who is both mentally ill and illiterate, signed a waiver agreeing to be deported to Mexico as an illegal immigrant without a hearing.

For months his mother searched for him in Tijuana and for months he was homeless in Mexico. He was found trying to cross the border back to the States.

In one month the U.S. government has deported at least 55 U.S. citizens according to an investigation by Associated Press (AP).

However, immigration lawyers say there are actually hundreds of US citizens who have been deported.

But the exact number will remain unknown, as long as no one is responsible for, or has chosen to take record.

AP say that its investigation revealed U.S. citizens have been detained for periods ranging from a day to five years and that according to U.S. law it is illegal to deport U.S. citizens or detain them for immigration violations.

It says lack of resources to deal with immigration issues results in the detention of citizens who are mentally ill, minorities, poor, children, and/or have outstanding criminal warrants. And that Americans of Hispanic decent are most likely to be illegally deported from the U.S..