In criminal cases, prosecutors do not get to choose their evidence. Every prosecutor would enjoy always having compelling forensic evidence and unimpeachable witnesses, particularly in preparing a serious case for trial. However, the vagaries of human existence dictate the exact opposite result: witnesses always have areas in which a defense attorney can “score points” on cross-examination and, in the real world, it is a rare case where inculpatory forensic evidence is located at the crime scene. I refer to these problems, extant in every criminal case, as ‘gremlins.’ It is a prosecutor’s obligation to address these ‘gremlins’ to a jury’s satisfaction.
The realities of criminal investigations are often lost on jurors who primarily receive their education about police and prosecutors from television. In the fantasy world of TV, a detective at a crime scene can quickly activate his handy portable tricorder, point it at a pool of blood or a spent cartridge case, and within seconds obtain a photograph of the murderer on the device, displayed prominently beneath a flashing 24-point, bright-red banner reading “match.”
Not surprisingly, it does not work that way in the real world, but these televised flights of fancy mean that many citizens enter the courtroom with unrealistic expectations about the prosecution’s ability to produce incriminating forensic evidence. Given the frequency with which this phenomenon is encountered, it has obtained a name: the “CSI effect,” eponymously named for a popular television program.
For prosecutors, one of the toughest facets of a trial is finding a way to gently broach the weaknesses in their cases and to provide credible explanations to the jury. Many new prosecutors flinch from addressing their “gremlins” because it just feels wrong to bring them to a jury’s attention. As a young attorney, I attended a trial advocacy course in which the instructor taught us that an attorney should never address or admit a weakness, for fear that the jury will believe the prosecution’s entire case is flimsy.
This is definitely the wrong approach. Above all else, a prosecutor must establish credibility with the jury. The jury does not have to like the prosecutor personally, although that obviously helps. However, the jury must inherently trust the prosecutor. There are always problems in a case. Pretending otherwise necessarily means that the prosecutor is losing credibility with the jurors. Furthermore, prosecutors who briefly raise and then provide credible explanations about their gremlins reap an added benefit: stealing the thunder of defense attorneys who are certainly going to raise those very weaknesses during their opening statements.
The reader may find this surprising, but in the real world of criminal investigations, it is rare to recover incriminating DNA or fingerprints from a crime scene. Criminals’ DNA is less likely to be found in cases where they wear gloves, do not touch the victim or when the perpetrator is only at the crime scene for a short time. DNA and fingerprints do not magically float through the air and any number of environmental factors, such as temperature, humidity or direct sunlight can affect the deposition or recovery of such forensic evidence. In many cases, small bits of DNA or partial fingerprints are recovered, but prove to be too scant to use for scientific comparison.
However, the police have an obligation to undertake a diligent search for such evidence at crime scenes. If they do not, they may be overlooking crucial evidence that could bring a violent criminal to justice and they become open to accusations of incompetence. The fact that forensic searches rarely produce incriminating evidence means that the more crime scene analyses a police detective undertakes, the more fruitless searches they likely produce.
As the reader recalls from an earlier column, prosecutors have an ethical duty to provide the defense with all material, even that which hurts their case. With regards to the ‘CSI Effect,’ this means that the prosecutor must disclose every fruitless police attempt to locate incriminating forensic evidence at the scene, handing the defense a potent weapon in their scorched-earth, win-at-all-costs attempt to cast doubt on the strength of the government’s case.
Next month, I will discuss how the ‘CSI Effect’ can impact a real-world case, and how prudent prosecutors can attempt to inoculate themselves from its negative influence on jurors.
The writer is Commonwealth’s Attorney for Alexandria.