Document analysis is an important method used to solve crimes. It is used to discover which documents are genuine or not and to detect forgery in the forms of alterations, additions, or deletions. It is also used for identifying people through handwriting samples. Document analysis can also be used to profile a criminal and to provide a testimony in court. Types of documents that can be used as evidence are recipts, ransom notes and letters. Document analysis is most commonly used to solve smaller cases like in privite practice or for local, state, or federal police agencies. In privite practice, document examiners usually examine wills, checks and ledgers, and other personal documents for signs of forgery. Document examining has been used since the 1800's.