Suspects who haven’t been arrested but have been asked to participate in a lineup should speak with a lawyer before agreeing.
Suspects who have already been charged with a crime have a right to have counsel present at a lineup, and should tell the police that they want a lawyer present, orally and in writing if possible, before the lineup gets underway. Suspects should not sign a “waiver of attorney,” which allows the police to conduct a lineup without having a lawyer present. If the police refuse to allow or wait for an attorney and go ahead with a lineup, the suspect should participate in it and later—through a lawyer—file a motion to suppress any resulting identification.
If no attorney is present, suspects can help guard their right to a fair lineup by following officers’ instructions and refraining from acting out so as to attract attention to themselves. Suspects should pay attention to the lineup procedures—and everything else that happens. As soon after the lineup as possible, they should write down everything they can remember, including all statements. A lawyer will later be able to parse through the written (and any verbal) account for any viable arguments in favor of suppressing the identification. Among the points to document are the number of people involved in and the setting of the lineup. Where were the participants standing? Did anyone look or dress differently from others? What did the officers say to whom?
Any notes that suspects make of their lineup observations should be marked “Privileged—For My Attorney Only” and not shown to anyone except a lawyer.
For more on handling lineups and the identification process in general, including challenges to procedure, see Nolo's page for Eyewitness Identification issues.