There are at least two ways in which to define “identification of a suspect.”
First, in any criminal case, the police have to identify who their suspect is. In some cases, it is obvious because they have caught the person in the act of the crime. In other cases, however, the police will have to do a great deal of work before they can identify anyone as a suspect. They might have to conduct many interviews with potential witnesses and they might have to thoroughly examine physical evidence in order to identify a suspect. Once they have done so, they can focus to some degree on investigating that person.
Second, it is often necessary for the police to ask witnesses to identify a suspect. In such cases, the witness might have seen someone that they do not know commit a crime or they might have seen him near the scene of a crime acting in a suspicious manner. When the police have identified a suspect, they must then give the witness a chance to identify him as well. They have to do so, however, in a way that will not prejudice the witness. They cannot simply bring the suspect in and say to the witness “we think this is the guy, what do you think?” Instead, they must follow approved procedures to get a valid identification of the suspect.