All police forces use a mixture of in-house services and those provided by external forensic suppliers to carry out forensic work. For example, crime scene investigators, who will generally be employed by a force, may find fingerprints and material which may carry traces of DNA. The fingerprints are compared with IDENT1, the national fingerprint computer system, which produces a shortlist of possible matches. The shortlist is then examined by fingerprint experts who work for the force Fingerprint Bureau to confirm a match. Analysis of material to produce DNA profiles is done by forensic suppliers rather than in-house. In other areas of forensic work, the balance between in-house and external services will vary depending on the nature of the material examined and decisions made by forces. Details of the position in each police force are not held centrally.