Law provides the basis for every police officer's actions. Without a complete understanding of criminal law, criminal procedure, and the rules of evidence, an investigator cannot hope to be successful in building a criminal case. Throughout history, humankind has sought mechanisms to ensure that its members conduct themselves in a manner that is acceptable to most of its members. These mechanisms are given a number of names, including norms, mores, and folkways. Most of these codes of conduct are taught to children and, over time, become part of the individual's unconscious behavior. When internal mechanisms of social control fail or appear to fail, cultures elevate proscription of the behavior to the status of law. It becomes an act defined and made punishable by law. Police investigators must know all the laws that exist in a jurisdiction and be prepared to use them as the basis for investigations and subsequent prosecutions.
A patrol officer was sent to an emergency room to take an accident report. Upon arriving, the officer was directed to a young woman who was wearing a large wig, a tightly fitting, low-cut top, and a tight, short skirt. Her attire reminded the officer that she was a prostitute working for a well-known local procurer. She had a large gash, approximately 6 inches long, on the left side of her face near her ear. She stated that she had fallen and struck a railing on the porch of her residence. The officer noted the implausibility of the story and suggested that she had been attacked by the procurer. She broke into tears and admitted that the officer was correct. He then encouraged her to use this event as reason to break from her association with the man and to tell the officer of the man's illegal activities. She then informed the officer that the person in question had a stolen television set in his living room. The officer used this and other information to obtain a search warrant. The house was searched, the TV was found, and the man was arrested for possession of stolen property. Investigators should be prepared to use any criminal law available to arrest and subsequently prosecute criminal offenders.
Criminal Procedure, Arrest Search, and Seizure Criminal procedural law, particularly the laws of arrest, search, and seizure, are the tools of the investigative craft that are used by an investigator on a daily basis. An understanding of the laws of arrest, search, and seizure begins with an appreciation of the different levels of proof and the types of action that may legally be taken with regard to each of them. The levels of proof that a police officer must commonly work with are listed in Table 2.1. Proof The levels of proof at each extreme of the continuum—no proof and absolute proof—are not usually a concern for the investigators as they work their cases. An understanding of the other five levels of proof—suspicion, reasonable suspicion, probable cause, preponderance of evidence, and proof beyond a reasonable doubt—is, however, central to the investigator's ability to investigate a crime and to enforce the law. They must therefore be examined in detail. Suspicion Suspicion is more than no proof but is not enough evidence to justify any type of governmental intrusion into any area where someone has an expectation of privacy. Unsubstantiated information from informants or anonymous phone calls and an investigator's "hunch" fall into this category. Suspicion may justify opening a case or at least delving into the facts more deeply. This type of evidence requires the investigator to seek corroboration of the information by checking records and/or by interviewing other individuals to determine if follow-up investigation is justified. CASE STUDY A patrolman received information in the form of an anonymous phone call made to the police station that a man with a history of burglary convictions had committed a residential burglary on the officer's beat. The patrolman examined the report of the preliminary investigation conducted by another patrolman to familiarize himself with
Literature: Michael F. Brown. Criminal Investigation Law and Practice. Second Edition.