Under immediate to general supervision, depending on the level in the series, assists in obtaining, preserving, and reporting admissible evidence for presentation in cases prosecuted by the District Attorneys Office; performs difficult criminal and civil investigations for the District Attorneys Office, Sheriffs Office, Municipal Police Agencies, and the Grand Jury; and performs related work as required. Some (I) to considerable (II) knowledge of the: substantive and procedural California Criminal, Civil, and Juvenile laws, and the modern techniques and practices of criminal investigation; laws of arrest, search and seizure, warrant and subpoena service, rules of evidence, and the admissibility of confessions and witnesses statements; functions and extent of authority of the District Attorneys Office; resources and techniques available in public and private criminal scientific laboratories and the latest medical-legal techniques in criminal investigation.