A “best practices” guide or policy for use by law enforcement agencies when asking victims and witnesses to crimes to view photographic line-ups of possible suspects would involve measures to ensure fairness and objectivity. There can be no suggestion that a law enforcement official is attempting, however discreetly or justifiably, to influence the outcome of a line-up because the law enforcement official is convinced of the identity of the guilty party.
When assembling a line-up comprised of individuals physically standing before victims or witnesses, or when using photographs, complete attention must be paid to presenting equitable images of each individual in the line-up. Often, local actors (i.e., from community theater groups) are asked to take part in line-ups because they are skilled at presenting themselves as other than they really are, and off-duty or plain clothes police officers might similarly insert themselves into line-ups as a way of gauging the witness’s veracity (in other words, if the witness or victim mistakenly picks out of a line-up an undercover police officer, the validity of the witness’s or victim’s testimony can be seriously impaired). Key, though, is that each individual in the line-up appears as normal as possible. There cannot be one photograph of a sneering suspect alongside photographs of law-abiding individuals; each photograph must look as innocent or as guilty as all the others. Any hint that the process is being manipulated, or has been conducted amateurishly, will undermine the integrity of a process crucial to the credibility of the criminal justice system.
A “best practices” policy for use in suspect line-ups must emphasize objectivity and fairness. Nothing is gained and much can be lost if the process is flawed. Good law enforcement officers understand that injustices happen to those with criminal pasts as well as to those who have never committed a crime. The objective of an investigation is identifying the correct individual. Manipulating the outcome of any part of the investigative process will almost certainly result in the wrong person being prosecuted, or the right person being prosecuted for the wrong reason.