WASHINGTON — Dozens of cases of possible wrongdoing by contract workers at the Department of Homeland Security agency responsible for citizenship, visas and green cards have sat idle for two years because internal investigators say they have been denied the authority to look into the allegations, interviews and documents show.
Investigators at the agency, United States Citizenship and Immigration Services, say they have repeatedly warned top managers that unaddressed allegations of corruption among contractors could put the immigration system at risk.
In 2015, they prepared a presentation, which was obtained by The New York Times, warning agency leadership that an inability to investigate contract workers had “possible national security implications.”
Internal agency documents show nearly 70 uninvestigated cases of alleged wrongdoing involving contract employees, including accusations that these workers were involved in bribery schemes, distribution of child pornography on agency computers and illegal use of government law enforcement databases.
The agency declined to respond to questions about its legal justification in stopping investigations into misconduct by contract workers. The same type of workers at other Homeland Security agencies are subject to internal inquiries.
“We can’t get an answer as to why,” said an investigator at the immigration agency, who spoke on the condition of anonymity because he is not authorized to publicly discuss internal policies. “We had investigated contractors before that, and it was no problem.”
John Roth, the Department of Homeland Security’s inspector general, said the inability of the internal investigations division at Citizenship and Immigration Services to investigate potential wrongdoing by contractors is a problem.
“The root cause is a failure of leadership to address the issue,” said Mr. Roth, whose independent office investigates cases that are referred to it, but only a small fraction of the overall number. “If they are right about not having the authority to investigate contractors, then they should seek a statutory fix.”
He added: “Investigators at C.I.S. have a right to be frustrated. Allegations ought to be investigated thoroughly. We don’t have the resources to investigate every complaint we get, so we depend on the internal affairs offices to help us.”
As one of his central domestic priorities, President Trump has vowed to overhaul immigration policies, but an inability to aggressively scrutinize potential internal corruption may make that more difficult.
The Citizenship and Immigrations Services agency also approves applications for asylum and is responsible for a variety of immigration documents.
United States immigration documents are sought-after by drug- and human-trafficking organizations, and even by foreign governments, to enable people to enter the country fraudulently.
Contract workers make up almost half of the immigration agency’s work force of nearly 20,000 people, yet are subject to limited oversight. These workers handle tasks like conducting criminal and national security background checks and taking fingerprints, and have access to sensitive government databases.
“There is currently no mechanism for investigating allegations of criminal and noncriminal misconduct conducted by contractors at U.S.C.I.S.,” the investigators said in their presentation to agency managers.
In a statement, the agency said that it cooperated with the Department of Justice and the inspector general, and that “ensuring the integrity of the U.S. immigration system is our highest priority.”
But investigators at the agency point to a Texas case from last year to contend that top officials are not taking the issue seriously.
The investigations division received a complaint that background checks on people who had just become citizens had not been completed until after a naturalization ceremony. Eight of the new citizens turned out to have criminal records, the complaint said.
When investigators reviewed computer records, they discovered that the background checks had been backdated to make it seem that they were completed in timely fashion. Records show most of the backdating was done by the contract employee.
This seemed a clear-cut case of wrongdoing to investigators, but it has been in limbo for more than a year because the investigations division isn’t allowed to speak to the contractor.
“We basically put these cases into a holding pattern because of the contractor issue, and they gather dust,” the investigator said.
The agency said it would not discuss specific cases.
While the Texas case remains unresolved, investigators say that past arrests and convictions of contract employees have given them reason to worry.
In 2011, Richard Abapo Quidilla, a contract employee working as a records custodian for Citizenship and Immigration Services in California, altered computer files to make it appear that 30 people who were in the country illegally were naturalized citizens.
Court records show that Mr. Quidilla deleted the names, birth dates and other personal information of naturalized citizens in an immigration database and used that information to create records for illegal immigrants, enabling them to get legal documents.
Investigators later determined that a least two of the people had used their faked citizenship to get passports, according to court records. One paid Mr. Quidilla at least $4,100 for his assistance, the records show, and the other gave him at least $1,300.
In 2014, Martin Trejo, a contract employee for the agency in California, was sentenced to 26 months in prison after being convicted in the theft of hundreds of immigration forms. According to court documents, Mr. Trejo stole the forms from a warehouse where he worked and sold them for about $5,000.
The documents ended up in the hands of a smuggling ring that used them to obtain hundreds of driver’s licenses for people living illegally in New Jersey, Nevada and other states, court documents said.
Both investigations had been referred to independent agencies, including the Department of Homeland Security’s Office of Inspector General, which is the lead agency for investigating wrongdoing. It can initiate its own inquiry or refer it back to the agency’s internal affairs offices. But the inspector general and agencies like the F.B.I. take few of the cases referred to them by investigators at Citizenship and Immigration Services
The inspector general’s office says it gets about 16,000 complaints a year from all agencies at the Department of Homeland Security, but has only 200 investigators. As a result, the majority of cases against contractors are never investigated, agents at the immigration agency say.
Investigators at the immigration office can refer complaints about contract workers to the agency’s contracting office, but the inspector general said that was inadequate.
“Simply referring the allegations to the contracting office did not fully address the allegations, nor did it prevent potentially harmful individuals from obtaining employment on different contracts,” the inspector general said in a report released in June.
Internal investigators at Citizenship and Immigration Services say not being able to investigate contractors is one of many problems at the agency. The investigators say they have too few people to look into the things that they are allowed to investigate.
Investigators say about 29 employees in the investigations division work on cases. The agency said it was authorized to have 60 people in the division, including supervisors and administrative staff. In contrast, Immigration Customs Enforcement, which has about the same number of employees and contractors, has about 200 investigators.