Identification evidence


Suspects in criminal investigations are often identified by witnesses. In criminal trials the prosecution rely on the suspect being identified.

Visual identification evidence is considered unreliable and innocent people have been convicted of crimes because of visual identification evidence. There are a number of reasons why visual identification evidence is not reliable including:

  • Poor lighting conditions, bad weather or the distance between the witness and the person when they saw them
  • The witness’s eye-sight, which may be in question
  • The witness may have been in shock when they saw the person, or may have only seen them briefly

Other types of identification evidence such as fingerprint evidence and DNA evidence are considered more reliable.

Visual identification evidence

The court must give the jury a warning about the dangers of accepting visual identification evidence to ensure that they don’t incorrectly interpret this evidence. This warning is a cautionary instruction and must state:

  • That honest witnesses with good observation opportunities have often made incorrect identifications
  • That the jury must carefully examine the identification evidence in light of all the circumstances
  • The need for particular caution
  • That the jury must be satisfied beyond all reasonable doubt that the identification was correct


At the early stages of an investigation the Gardaí will often show photographs of suspects to a witness. Before doing this, they should get a detailed description of the suspect from the witness, as this can show how strong the witness’s memory of the offender is, before they are shown photographs. The witness should be shown photographs of many possible suspects.

If a witness identifies a suspect using photographs and the prosecution wants to put this evidence to the jury, the defence counsel can challenge this with the judge in the absence of the jury. As, if the photograph shown to the witness came from Garda files, the jury would realise that the suspect had been photographed by the Gardaí on a previous occasion and this could prejudice the jury. The judge will decide whether this evidence should be put to the jury.

Photofits and identikits

A photofit or an identikit picture is a sketch of someone’s face, which is made using descriptions given by people who have witnessed a crime. The Gardaí use these pictures in criminal investigations to help them identify potential suspects. They are not really used in criminal trials as they are not considered to be real evidence, unlike a photograph or video. This means that they would not be valued as identification evidence in court. Perhaps the best way to describe them is as an aid to a criminal investigation.

Identification parades

If the Gardaí have already identified a suspect, they should not show the witness photographs of the suspect, but should have an identification parade (ID parade). This is because if the witness has already seen a photograph of the suspect, it may affect their judgement at the ID parade. If the suspect is shown photographs before the ID parade, the judge will warn the jury at the end of the trial that the ID parade is suspect evidence because the witness had already seen a photograph of the accused.

ID parades depend on the suspect’s co-operation. If a suspect refuses to participate, the Gardaí can get identification by informal means (for example, where a witness points out the suspect on the street). However, informal identification may not be admitted as evidence in certain situations, it depends on the circumstances of the case.

A formal ID parade is much more reliable than informal identification as it is a controlled process and the suspect’s solicitor can attend to ensure that the process is carried out correctly.

Rules for ID parades

While ID parades are frequently used by the Gardaí, the process is not provided for in law. However, there are a number of rules about ID parades, which have developed over time as a result of case law in Ireland. The main rules about ID parades are:

  • That they should be conducted by a Garda officer who is not connected with the crime but who has been made familiar with the circumstances of the case and has been given information about the witness
  • The witness should not see the accused being arrested or taken from custody to the ID parade room
  • If several witnesses are needed to identify the suspect, they should be kept apart before and after the parade, to minimise the chances for them to consult with each other about the ID parade
  • The witness should be asked to identify the suspect from a line of 8 to 12 people. These people should be chosen because they look similar to the suspect.
  • When the volunteers in the ID parade have been arranged in a line, the suspect should be asked if they have any objections to the composition or appearance of the parade
  • When the parade is completed, the accused and their solicitor should be asked whether they have any comments to make about the parade
  • Details of the parade and any objections made by the accused or the solicitor must be recorded
  • If a witness fails to identify the accused, the prosecution should disclose this fact to the defence

Fingerprint evidence

Fingerprint evidence is an accepted form of identification, but it must be given by an expert witness (a fingerprint expert). In order to use fingerprint evidence, the Gardaí or prosecution must be able to match a fingerprint left by a culprit at the crime scene with that of fingerprints taken from the accused in a controlled situation (that is, taken in a Garda station). In certain situations when you are detained after you are arrested you must provide the Gardaí with your fingerprints.

DNA evidence

The Criminal Justice (Forensic Evidence and DNA Database System) Act 2014 gives the Gardaí the power to take certain DNA samples from people detained after arrest under:

The Gardaí take these samples to find out if the person was involved in committing a crime. This way of identifying suspects can also be used to eliminate suspects.

These samples can only be collected if it has been authorised by a garda not below the rank of Inspector. The garda must have reasonable grounds to believe that the person was involved in committing the offence they were arrested for, and that collecting the DNA evidence will prove or disprove their involvement.

DNA samples

DNA samples collected from people detained under the laws above can be used as evidence. These DNA samples are divided into intimate and non-intimate samples.

Non-intimate samples include:

  • Saliva
  • Hair other than pubic hair
  • A nail or any material found under a nail
  • A swab from any part of the body including the mouth, but not from any other body orifice or a genital region
  • A skin impression

Non-intimate samples can be collected by the Gardaí. If you do not consent to having a non-intimate sample taken, the Gardaí can use reasonable force to collect the sample.

Intimate samples include:

  • Blood
  • Pubic hair
  • Urine
  • A swab from a body orifice or a genital region other than the mouth
  • A dental impression

The Gardaí must get your consent to take an intimate sample and the sample must be taken by a doctor or dentist, as appropriate. Also if possible, the sample should be taken by a medical professional of the same sex as the person giving the sample.

Protected persons

Children under the age of 14, and people who don’t have the capacity to understand the DNA testing process and cannot give consent are known as protected persons. The Gardaí must get consent from a protected person’s parent, guardian or the Court before taking a DNA sample from a protected person.

The DNA database

Under the Criminal Justice (Forensic Evidence and DNA Database System) Act 2014 a DNA database was established in Ireland. This database is used to help investigate and prosecute criminal offences.

When DNA evidence is recovered from a crime scene it is entered into the crime scene index in the DNA database. When DNA evidence is taken from someone in accordance with the 2014 Act, (for example, a suspect who has been arrested and detained under one of the laws above) it is entered into the reference index on the database.

The crime scene index is then cross-referenced with the reference index to see if there is a match. If there is a match, this can be used as evidence to prosecute an offence.

More information is available in the document on DNA evidence.

Further information

You should get legal advice for more detailed information on this.

Page edited: 24 April 2019