Line-ups are also not mandatory in NSW, so suspects cannot be forced to participate, which Inspector Taylor believes is another reason they are not used frequently by police to develop cases. Despite this, he claims that courts still regard line-ups as "the finest method of identification."
Police line-ups are still commonly used by law enforcement agencies across the world. They allow officers to show several potential suspects together, thus increasing the chances that the right person will be identified.
They can be useful tools for investigators to quickly rule out certain persons as possible suspects. For example, an officer may show photo arrays of all known crime victims to see if they can identify their assailant. If someone matches one or more photos, then that person becomes a suspect. Police departments around the country use computer programs to create photo arrays that contain images of unknown suspects. Officers then review these lists of photos with witnesses or people who may have information about the case and ask them to pick the person they think is most likely responsible for the crime.
People tend to remember faces better than names, so using photographs instead of live witnesses helps officers eliminate innocent people from consideration. The photo must be clear and recent (within the last few years), because older photographs may not yield good results when trying to identify suspects.
Line-ups can also help officers find the right person even if they don't know exactly what happened.
To avoid going to court or being arrested, the NSW Police Force will never telephone a member of the public and demand money over the phone. If you receive an unexpected call from someone claiming to be from the police and begins demanding for personal information or threatening you, hang up the phone. Any contact made with you by these individuals is entirely false and they are not authorised to act on behalf of the Police Force.
However, there are times when officers may need to contact people who have been identified as potentially involved in crime. This may include witnesses or victims. Officers would only do this with permission from their supervisor. Any officer that makes an unauthorised call could face disciplinary action.
Police officers also make traffic stops. During a stop, officers must communicate with you but cannot discuss the details of your case until you have been taken into custody. Agreeing to look at photos or giving officers your name and address is enough communication for now.
If you don't agree to look at photos or give your information, this could be used as evidence that you have committed a crime. The police can then take you into custody and read you your rights.
Finally, police conduct searches. During a search, officers must obtain your consent before searching any property or item that is within your immediate control. This includes containers such as bags or boxes that might contain evidence.
When employing their police powers, plainclothes cops must identify themselves. They are not, however, compelled to identify themselves on demand and may, in some cases, lie about their position as a police officer (see sting operation).
In most states, it is a crime for any police officer to fail to disclose his or her identity when making an arrest. The exception is if the suspect fails to comply with a lawful order to stop which would make an arrest necessary. In that case, the officer does not have to reveal himself or herself before making the arrest.
These are the only situations in which an undercover officer does not have to identify himself or herself. Otherwise, officers are required by law to identify themselves whenever they engage in activity within their capacity as police officers.
For example, an officer who stops someone for a broken tail light has two duties: to issue a summons for the traffic violation and to investigate whether the driver was impaired by alcohol or drugs. To perform these tasks properly, the officer must determine whether there is enough evidence of impairment to require further testing or to justify a criminal charge. For this purpose, the officer must be able to provide his or her name and contact information during the course of the investigation.
Pretrial lineups, in which eyewitnesses attempt to identify a criminal suspect from a group of persons with similar appearances, may be a valuable piece of evidence in a California criminal jury trial. However, witness identifications in lineups are frequently untrustworthy, and examples of incorrect eyewitness identification are all too prevalent. Research has shown that eyewitnesses often make errors when attempting to identify suspects from photographs or videotapes of crimes.
Lineup procedures should include at least two photos of the same person, if possible taken under controlled conditions within minutes of the crime being committed. If only one photo is used, research shows that the chances of correctly identifying the suspect increase if there is a good quality photograph available.
Eyewitnesses should not be allowed to study the photos before viewing the lineup. They should be presented one by one, without comment or discussion by the officers conducting the investigation. Officers should use caution not to lead witnesses during this process.
Witnesses must be informed of all reasonable attempts that will be made to find the perpetrator, as well as their right to refuse to answer questions or participate in the lineup. If a witness refuses to cooperate, their results cannot be included in the case file.
Police departments should adopt specific guidelines for photo lineups to ensure fairness for both suspects and witnesses.