大陪審
Although the vast majority of criminal cases in Wisconsin are begun by a district attorney filing a criminal complaint, some cases are commenced as the result of a grand jury or John Doe investigation. Grand jury and John Doe investigations are secret proceedings for which witnesses may be subpoenaed. Grand jury and John Doe proceedings are generally used when investigators need to take testimony under oath or compel a witness to testify in order to gather sufficient evidence to issue a criminal complaint.