An immigration "detainer," often called an "immigration hold," is a notice that Department of Homeland Security (DHS) agents issue to local, state and federal law enforcement agencies. It is a primary tool ICE uses to apprehend suspected noncitizens being held by these authorities.

In more than two out of three (77.4%) of the detainers issued by ICE, the record shows that the individual who had been identified had no criminal record — either at the time the detainer was issued or subsequently. For the remaining 22.6 percent that had a criminal record, only 8.6 percent of the charges were classified as a Level 1 offense. See Figure 1.

Figure 1. Number of ICE Detainers Issued, by Criminal History

ICE inexplicably withheld any information on the nature of the crime for which the individual had been convicted. However, as TRAC reported in February 2012, the ICE basis for classifying individuals as "serious" offenders — that is, Level 1 — appears to be flawed, since their records show that all too often the most serious Level 1 offenders have only been convicted of traffic violations and immigration violations (illegal entry) rather than some more serious offense. Accordingly, it appears likely that far fewer than even this small proportion of 8.6 percent actually would meet the more objective standards of having been convicted of crimes that pose a serious threat to national security or public safety.

Detainer notices ask agencies to continue holding individuals so that DHS agents can take them into custody. A detainer is often triggered when a local or state agency books an individual into jail and sends the individual's fingerprint records to the FBI to see if the individual has any criminal record. These fingerprint records are now routinely passed onto ICE to check against its files.

While over 3,500 different detention facilities received one or more ICE detainers, ICE did not release essential information about them — inexplicably, for example, withholding even the state where they were located. The total number of detainers for each facility, along with whether ICE had any record that the individuals were ever convicted of any crime, can be found in Table 1. But because of the missing information, care should be exercised for facilities with common names since if there is more than one facility in the country with that name, the statistics will combine their counts.