Under Japanese law, DNA samples may be taken and tested when the investigation starts. In order for these procedures to take place, it is not necessary that either the suspect be arrested, or that criminal charges be filed. The formalities required in relation to the collection of samples will vary depending on the manner the collection of samples takes. According to Japanese law, there is no differentiation between persons in relation to the collection of samples. In effect, therefore, the same rules apply to all people who are suspects. Most DNA tests are carried out at institutes that belong to the police. They conduct four kinds of DNA tests: 'MCT118 type test', 'HLADQ type test', 'TH01 type test' and 'PM inspection test'. The police established a set of internal guidelines for the practice of DNA tests in 1992. They provide for the method of tests and the contents that should be included in the written expert opinion.