A private investigator should be hired if all reasonable sources of readily available information have been exhausted and if neccessary added information must be obtained outside normal channels and methods. Security professionals are a good referral source for private investigators. Other sources include yellow page listings in the telephone directory and directories of professional organizations such as the National Council of Investigation and Security Services (NCISS), the Council of International Investigators, the World Association of Detectives, and the National Association of Legal Investigators. Qualified private investigators also belong to the Former Special Agents of the Federal Bureau of Investigation. Each of these associations requires detailed applications, extensive background checks, and licensing. Qualified investigators should also be able to provide lists of references. A good investigator usually specializes in one field such as surveillance, criminal defense, domestic relations, or computer fraud. Fees range from $25 to $100 per hour. Most investigators require a retainer or prepayment covering up to 50 percent of anticipated costs. Because confidentiality is important, clients may want investigators to sign legal agreements to protect any confidential or proprietary information uncovered in investigation. While investigators cannot provide copies of police records, tax returns, or credit profiles, a written report on the investigation is standard. A directory of professional associations is provided.