Manuel Guerra Vasquez has been deported to Mexico before, but each time he returned to Texas. Even though he was born in the Mexican state of Tamaulipas, the 61-year-old claims he’s a U.S. citizen. Proving he’s entitled to citizenship has been difficult. John Bray, an immigration and criminal defense attorney in Dallas, is helping Guerra Vasquez and several of his family member prove they’re citizens. That’s because the family’s matriarch Cruz Rodriguez-Vargas Guerra, who died a few years ago, was born in Kansas in 1924, a fact they say was common knowledge in the family.  “There are thousands of people who are U.S. citizens and don’t even realize it and it really does require a thorough investigation of the factual circumstances and the family circumstances for each person,” Bray says. Denise Gilman, who works at the immigration clinic at the University of Texas in Austin, said these cases are likely more common among families who live along the border, such as migrant farmworkers who routinely traveled back and forth between the two countries. Gilman said whether someone qualifies for U.S. citizenship depends on when that person was born and what was written in law then because the law has changed numerous times. The issue caught the attention of the Government Accountability Office in 2021 when it issued a report. In its findings, the GAO reported that as many as 70 U.S. citizens had been deported over the previous 5 years.