ICE raids generally are the results of months (or even years) of investigation by Homeland Security Investigations (HSI). Before a “raid” is conducted, a search warrant must be issued. To obtain a search warrant, HSI must show that facts establish probable cause to believe that there are violations of federal law, i.e., the company is willfully and unlawfully employing illegal aliens.

How does HSI gather the evidence it needs for the search warrant? Based primarily upon search warrant applications, here are some of what the agency does:

• HSI may employ confidential informants. These could be undocumented workers who have been arrested, and are subject to deportation, but will gather information for HSI in exchange for some benefit – such as a work permit. Confidential informants may wear wires and record audio and video evidence.
• Employ confidential informants who are U.S. citizens or others who have been involved in the employment verification process and who agree to provide information in exchange for immunity.
• Receive information from its tip line – these may even come from disgruntled employees.
• Question undocumented workers who are arrested away from the worksite about their employment and pay stubs to gather evidence of illegal employment.
• Undocumented aliens who are arrested and put into the Alternatives to Detention (ATD) program often are tracked using ankle bracelets or other GPS, telephonic devices, or SmartLink devices. Individuals in this program do not have work authorization. HSI may follow these aliens electronically and can determine if they are spending hours at a time at a specific worksite.
• Review state wage reports, compare those against law enforcement databases, and identify theft victims to see whether employees are using a stolen identity.
• Review E-Verify tentative non-confirmation notices (TNCs) to see if they have been resolved or it may simply request E-Verify Query Extracts. Comparing the E-Verify Query Extracts to quarterly wage reports, ICE can determine if all new employees were run through the E-Verify system.
• Collaborate with other federal agencies such as the IRS, to review company tax filings, or the Social Security Administration, to review No-Match letters.

The raid is not the end of the investigation. HSI uses the information it gathers, including reviewing company records and interviewing arrested workers, to continue its investigation. HSI also may continue to monitor the same worksite for possible new violations.