The Critical Connection Between Prosecutors and Police:
The Screening Function
Submitted by: Norm Kiger
The perception that members of the public have of how prosecutors and police interact might arise from what they see on television, in films, in newspapers, and in other public media. Because those media have limitations on time and space, the public does not see the depth and intricacies of the interplay between prosecutors and police. That interplay is crucial to achieving the ultimate goal of law enforcement: justice.
This discussion will focus on screening major crimes such as murder, aggravated assault, and robbery. A starting point is a general consideration of the varying roles of police, prosecutors, and defense attorneys. As is well depicted in films and television shows, the primary role of the police during the investigation of a consummated crime is to gather and preserve all the evidence that can be found, including evidence that may implicate a suspect, as well as evidence that may tend to exonerate the suspect or implicate someone else. Along the way, if there is sufficient evidence to establish probable cause that a suspect committed the crime, the police may arrest the suspect, typically with a judicially issued arrest warrant. Similarly, if there is probable cause to believe that evidence of the crime may be found at a particular location, the police may obtain a search warrant in order to seize that evidence. It is not the function of the police to judge whether a suspect is guilty; rather, it is their function to present all of the gathered and preserved evidence to a prosecutor.
At this point, in examining the role of the prosecutor, it is useful to jump ahead to the role of the defense attorney. The defense attorney’s objective when representing a client who has been charged with a crime is to prevent the client from being convicted or, if the client is convicted, to obtain for the client a lenient sentence. Defense attorneys must abide by ethical rules that prohibit them from presenting perjured testimony in a trial or from deliberately presenting false evidence. But the defense attorney’s primary legal obligation is to represent the client, not to seek overall justice. Accordingly, the defense attorney is under no obligation to disclose to the prosecution evidence implicating the client that the prosecution does not possess.
By contrast, the prosecutor has an obligation to seek overall justice. In that regard, the prosecutor has obligations to all those people within the jurisdiction, including those suspected of crimes. So when the police present the prosecutor with a body of evidence in a case, the prosecutor must weigh the evidence against the legal requirements that establish the elements of the crime. In weighing the evidence, one of the things the prosecutor must assess is whether the evidence appears sufficient to convict the suspect, either before a jury or before a judge sitting without a jury. In the real world of criminal justice, in some cases, not all evidence points in the same direction. As a critical part of evidence assessment, the prosecutor must consider whether any of the evidence tends either to exonerate the suspect or to implicate someone else. If the actual perpetrator is prosecuted without sufficient evidence to establish guilt beyond a reasonable doubt, then the suspect likely will be acquitted and will have gotten away with the crime. Even worse, if the suspect is prosecuted despite some evidence that someone else was the perpetrator, the result might be that the suspect either is acquitted or is wrongfully convicted. Either way, the actual perpetrator has not been brought to justice. If it appears that the evidence in a case is insufficient for a conviction or that some of the evidence is ambiguous with regard to the suspect’s guilt, the prosecutor will work with the police to pursue fresh lines of investigation that might yield additional evidence to resolve the issues. This is a team effort in which all the participants – prosecutors and police – are mindful of the imperative that when there has been a serious crime, especially one involving violence or the loss of life, the person or persons who actually committed the crime must be brought to justice.
When there needs to be an additional investigation to resolve evidentiary issues, one of the methods is to re-interview witnesses who have already given statements. Often, when prosecutors and police review witness statements, especially after comparing one witness’s statement with the statements of other witnesses or with physical evidence, additional lines of inquiry emerge. It is not uncommon in criminal investigations that a witness might give a statement containing incomplete, misleading, or outright false information. In preparing to re-interview a witness, it is useful to consider who should conduct the re-interview: the original interviewing police officer, a different police officer, or the prosecutor. Many police officers, especially homicide detectives, have developed exceptional people skills that enable even reluctant witnesses to voluntarily disclose all that they have observed. During the course of additional investigation, additional witnesses might be identified who, upon being interviewed, provide new information regarding the offense.
After a prosecutor’s review, most criminal cases are determined to have sufficient evidence to proceed to trial. Usually, the case is first presented to a grand jury, which returns an indictment, after which the case is scheduled for trial. Throughout the process, in contrast with the obligations of the defense attorney, the prosecutor has an obligation to disclose to the defense attorney any information tending to exonerate the suspect or that might lessen any punishment that the suspect might receive. The investigation is still open throughout the trial, during which additional evidence might be discovered and introduced. If the police and prosecutor have diligently carried out their duties, the judge and jury in the trial will be able to render a just verdict.
Those cases in which the evidence is determined to be insufficient, even after additional investigation has sought additional evidence, do not proceed to a grand jury or to trial. Those cases may remain “open” for an indefinite period. Many such “cold cases” have been reopened years later when additional evidence is discovered. Although there might be a general statute of limitations that would prevent prosecution after a specified number of years, many states do not have such limitations for major violent crimes. When cold cases are brought to trial after the discovery of new evidence, police and prosecutors have an opportunity to hold perpetrators to account and to provide final justice on behalf of victims and the community.
