The Handbook of Forensic Services provides guidance and procedures for safe and efficient methods of collecting, preserving, packaging, and shipping evidence and describes the forensic examinations performed by the FBI's Laboratory Division and Operational Technology Division. The successful investigation and prosecution of crimes require, in most cases, the collection, preservation, and forensic analysis of evidence. Forensic analysis of evidence is often crucial to determinations of guilt or innocence. The FBI has one of the largest and most comprehensive forensic laboratories in the world, and the FBI Laboratory is accredited by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board. The forensic services of the FBI Laboratory Division and the Operational Technology Division are available to the following: FBI field offices and legal attaches, U.S. attorneys, military tribunals, and other federal agencies for civil and criminal matters, State, county, and municipal law enforcement agencies in the United States and territorial possessions for criminal matters. All forensic services, including expert witness testimonies, are rendered free of cost; however, the following limitations apply: No examination will be conducted on evidence that has been previously subjected to the same type of examination. Exceptions may be granted when there are reasons for a reexamination. These reasons should be explained in separate letters from the director of the laboratory that conducted the original examination, the prosecuting attorney, and the investigating agency. No request for an examination will be accepted from laboratories having the capability of conducting the examination. Exceptions may be granted upon approval of the FBI Laboratory Director or a designee. No testimony will be furnished if testimony on the same subject and in the same case is provided for the prosecution by another expert. No request for an examination will be accepted from a nonfederal law enforcement agency in civil matters. In addition, when submitting evidence to the FBI Laboratory, contributors acknowledge the following: FBI examiners will choose appropriate technical processes to address the contributor's request for examination. Depending on the caseload of the Laboratory and the needs of the contributor, evidence examinations may be subcontracted. An FBI Laboratory Report of Examination may contain the opinions and/or interpretations of the examiner(s) who issued the report. "