NewsNation) — Border officials say migrants crossing into the United States using fake documents — or ditching them altogether — are making it harder to identify them.

NewsNation’s Ali Bradley reports coming across piles of discarded documents along the U.S.-Mexico border.

When people do come in without a form of identification, they are processed by Customs and Border Protection using whatever information is provided by the migrant themselves.

“The problem, though, is that we’re basically taking people’s word for it — that they are who they say they are, they’re from whatever country they’re from, when they say they don’t have any criminal history,” Jon Anfinsen, vice president of the Border Patrol Council, said. “Hopefully, they’re telling the truth. But we have no real way of knowing that.”

Most countries don’t share criminal information with the United States. A source tells NewsNation that unless a host nation puts out an international alert, they don’t have access to other countries’ databases.

Documentation has been hard to find for the suspect accused of killing 22-year-old Georgia nursing student Laken Riley.

Jose Ibarra, 26, a Venezuelan immigrant who authorities say entered the United States unlawfully, faces murder and assault charges in connection to Riley’s death. Upon his arrival, Ibarra gave law enforcement what he said was his Venezuelan identification number, though it was not valid: It included an extra digit.

NewsNation sources in Venezuela were not able to find Ibarra in the national database. When they removed the last number in the identification, the person who popped up in their system was a woman. As of right now, it is unclear if Ibarra has a criminal record in Venezuela.

Ibarra’s immigration status has been the topic of discussion among lawmakers in the wake of Riley’s death.

However, multiple studies, including one conducted by the National Academy of Sciences, shows U.S. born-citizens actually contribute more to crime rates than undocumented immigrants.

The Academy’s study, based on Texas Department of Public Safety data, show that native-born citizens are more than twice as likely to be arrested for violent crimes. Citizens are also more likely to engage in every type of felony crime except traffic violations.

The Associated Press contributed to this report.