The problem became apparent after department employees working on citizenship applications did not have access to fingerprint records of some individuals, according to the audit. Roth said many paper fingerprint files from the past have not been digitized and, as a result, would not show up in searches when the immigrants applied for citizenship under a different name.
"This situation created opportunities for individuals to gain the rights and privileges of U.S. citizenship through fraud," he said in a statement.
The audit recommended that any fingerprints in outstanding cases be added to the government's database and that officials create a system to evaluate the individual cases of immigrants who were improperly granted citizenship. DHS officials agreed with the inspector general's report and said the government is working on implementing changes and corrective actions.