USCIS will look for cases where it believes a person obtained U.S. citizenship by error, fraud, mistake , using false name or identity - and will refer potential denaturalization cases to the US Department of Justice.
The USCIS couldn't assure compliance with the law because old paper-based records containing fingerprint information from the FBI and DHS can’t be searched electronically. All old paper-only records need to be digitized bfore they can be searched electronically.
In 2008, USCIS identified 206 people who used different names or other biographical information to gain US citizenship or other immigration benefits. This was possible because ICE did not consistently add digital fingerprint records of immigrants whom agents encountered until 2010.
On September 18, 2016, the DHS Office of the Inspector General issued a report entitled Potentially Ineligible Individuals Have Been Granted U.S. Citizenship Because of Incomplete Fingerprint Records.
The report found that that "USCIS granted U.S. citizenship to at least 858 individuals ordered deported or removed under another identity when, during the naturalization process, their digital fingerprint records were not available."Overall, the report found that fingerprint records were missing from hundreds of thousands of cases.
In June 2018, USCIS Director L. Francis Cissna told in an interview that USCIS is hiring several dozen lawyers and immigration officers to review cases of immigrants who were ordered deported and are suspected of using fake identities to later get green cards and citizenship through naturalization.Cissna said the cases would be referred to the U.S. Department of Justice, whose attorneys could then seek to remove the immigrants' citizenship in civil court proceedings. In some cases, government attorneys could bring criminal charges related to fraud.
Until now, the agency has pursued cases as they arose but not through a coordinated effort. It is expected that USCIS new denaturalization office Los Angeles will be running by next year but investigating and referring cases for prosecution will likely take longer.
More about denaturalization effort here.