In this Aug. 31, 2015, photo, an unidentified Immigration and Customs Enforcement, ICE deportation officer reviews forms required to issue a detainer asking local law enforcement to hold someone until ICE agents can pick the person up, at the the Pacific Enforcement Response Center in Laguna Niguel, Calif. The center is where ICE issues detainers for immigrants arrested by local law enforcement who are suspected of being in the country illegally. (AP Photo/Amy Taxin)

Immigration detainers often issued by California center

Immigration authorities had begun issuing detainers based on electronic data after getting access to fingerprints from jail bookings under enhanced law enforcement information-sharing after the 2001 terrorist attacks.