The Department of Homeland Security on Monday said it is set to begin collecting DNA samples from its arrestee and detainee populations under a new rule enabling the department to comply with a 2005 law.

Current plans call for Customs and Border Protection (CBP) to immediately begin a phased implementation of DNA sample collection of detained illegal immigrants and certain U.S. citizens and lawful permanent residents that rolls out over the next three years leading to full implementation. Under the operating concept, select CBP agents and officers will use swabs to collect DNA from the targeted populations and send the samples to the FBI for processing.

The plans are outlined in a DHS Privacy Impact Assessment dated Jan. 3 and released on Jan. 6. In addition to CBP, Immigration and Customs Enforcement (ICE) will also participate in the DNA collection efforts.

ICE, at a single Enforcement and Removal Operations facility, will pilot the DNA sample collection to help it understand its operational and resource needs leading to full implementation at all of its locations. The DHS notice says that ICE Homeland Security Investigations won’t participate under the new rule as the agency already collects DNA samples for arrestees and detainees as part of criminal prosecution efforts.

The FBI will process and store the DNA results in its Combined DNA Index System, better known as CODIS, National DNA Index System.

The procedures don’t appear to involve the use of Rapid DNA by the DHS agencies, as used by CBP last year to weed out fraud in claimed familial relationships of migrants entering the U.S. In fact, the processing times expected under the emerging use of DNA aren’t expected to always be immediately useful to migrants in custody.

“The time it may take for the FBI Laboratory to process a DNA sample submitted by CBP or ICE may result in any potential match to CODIS occurring after the subject is no longer in CPB or ICE custody,” DHS says. “Therefore, it is unlikely that CBP or ICE would be able to use a DNA profile match for public safety or investigative purposes prior to either an individual’s removal to his or her home country, release into the interior of the United States, or transfer to another federal agency.”

Rather, the sample collections will allow DHS to comply with the 2005 DNA Fingerprint Act, it says.

The Department of Justice, last October in its proposed rulemaking, said that DHS sample collection “could be essential to the detection and solution of crimes [aliens] may have committed or may commit in the United States.”