A show up can only be conducted when:

A show up is a specific identification procedure used in criminal investigations where a witness or victim is presented with a suspect shortly after a crime has occurred. The purpose of a show up is to quickly establish whether the witness can identify the suspect as the perpetrator.

The conditions for conducting a show up include the necessity of having a suspect who matches the description provided by the witness or victim. This context is crucial because it supports the idea that the identification can occur in a timely fashion after the crime, potentially leading to the apprehension of the suspect before they can alter their appearance or flee the area.

The option stating that a show up can be conducted when there is a reasonable belief that the perpetrator has changed appearance is also valid since changes in appearance could impact the reliability of witness identification. Law enforcement needs to ensure that they are acting before any changes can occur, making timing essential.

Lastly, the suspect being randomly available is also relevant since the identification process needs to occur as soon as possible after the incident. If a suspect conveniently matches the description and is available for a show up, it increases the likelihood of a legitimate identification.

Therefore, all these conditions must work together to justify the use of a show up, establishing that the procedure is most useful when the