Detectives and Criminal Investigators

Key Responsibilities

• Search for and collect evidence, such as fingerprints, using investigative equipment.
• Perform undercover assignments and maintain surveillance, including monitoring authorized wiretaps.
• Check victims for signs of life, such as breathing and pulse.
• Obtain summary of incident from officer in charge at crime scene, taking care to avoid disturbing evidence.
• Preserve, process, and analyze items of evidence obtained from crime scenes and suspects, placing them in proper containers and destroying evidence no longer needed.
• Prepare charges or responses to charges, or information for court cases, according to formalized procedures.
• Provide information to lab personnel concerning the source of an item of evidence and tests to be performed.
• Secure persons at scene, keeping witnesses from conversing or leaving the scene before investigators arrive.
• Determine scope, timing, and direction of investigations.
• Examine records and governmental agency files to find identifying data about suspects.
• Prepare and serve search and arrest warrants.
• Note, mark, and photograph location of objects found, such as footprints, tire tracks, bullets and bloodstains, and take measurements of the scene.
• Block or rope off scene and check perimeter to ensure that entire scene is secured.
• Collaborate with other offices and agencies to exchange information and coordinate activities.
• Obtain and verify evidence by interviewing and observing suspects and witnesses or by analyzing records.
• Question individuals or observe persons and establishments to confirm information given to patrol officers.
• Notify command of situation and request assistance.
• Organize scene search, assigning specific tasks and areas of search to individual officers and obtaining adequate lighting as necessary.
• Notify, or request notification of, medical examiner or district attorney representative.
• Testify before grand juries concerning criminal activity investigations.
• Secure deceased body and obtain evidence from it, preventing bystanders from tampering with it prior to medical examiner's arrival.
• Record progress of investigation, maintain informational files on suspects, and submit reports to commanding officer or magistrate to authorize warrants.
• Examine records to locate links in chains of evidence or information.
• Maintain surveillance of establishments to obtain identifying information on suspects.
• Prepare reports that detail investigation findings.
• Obtain facts or statements from complainants, witnesses, and accused persons and record interviews, using recording device.
• Identify case issues and evidence needed, based on analysis of charges, complaints, or allegations of law violations.
• Analyze completed police reports to determine what additional information and investigative work is needed.
• Summon medical help for injured individuals and alert medical personnel to take statements from them.
• Participate or assist in raids and arrests.