What makes your choice better than other options?

You are the chief of police advising officers on an arrest that has just been made on a double homicide. Your officers inform you that they have several eyewitnesses who claim they can identify the suspect. You want to make sure that the identification is as airtight as it can be. What identification procedure(s) do you advise your officers to use? Why? What makes your choice better than other options? All initial posts should reference the textbook, Criminal Law & Procedure, and, at least one outside source.