For the purposes of this report, "criminal alien" refers to any alien who has been convicted of certain serious crimes in the United States. The Anti-Drug Abuse Act of 1988 requires the Attorney General to devise and implement a system to make available to Federal, State, and local authorities, on a 24-hour basis, the investigative resources of the INS to determine whether individuals arrested for aggravated felonies are aliens. To meet this requirement, INS established the Law Enforcement Support Center (LESC), whose pilot operations began in July 1994. When individuals arrested for aggravated felonies identify themselves as being foreign-born, the local law enforcement agency sends a request to LESC to determine whether these individuals are aliens and thus possibly subject to deportation. This study found that the criminal alien information in INS' Deportable Alien Control Systems (SACS) database and the corresponding Central Index System (CIS) files is incomplete and inaccurate. According to the statistical sample of criminal aliens recorded in DACS, important information contained in INS paper files was missing from, or incorrectly entered into, the DACS electronic files. Further, DACS did not contain records of all the paper files it should have included, and some of the criminal alien files it did contain lacked the information needed to show that these persons were criminal aliens. Recommendations for improving the system are offered, and INS' comments on this report's findings are included. Appended description of study scope and methodology