Federal Immigration and Nationality Act State and local law enforcement officials have the general power to investigate and arrest violators of federal immigration Section 8 USC 1324(a)(1)(A)(iv)(b)(iii) State and local law enforcement officials have the general power to investigate and arrest violators of federal immigration statutes without prior INS knowledge or approval, as long as they are authorized to do so by state law. There is no extant federal limitation on this authority.
The 1996 immigration control legislation passed by Congress was intended to encourage states and local agencies to participate in the process of enforcing federal immigration laws. Immigration officers and local law enforcement officers may detain an individual for a brief warrantless interrogation where circumstances create a reasonable suspicion that the individual is illegally present in the U.S. Specific facts constituting a reasonable suspicion include evasive, nervous, or erratic behavior; dress or speech indicating foreign citizenship; and presence in an area known to contain a concentration of illegal aliens.