Although police, prosecutors, and jurors have produced convictions based only on eyewitness identifications of suspects, there is now a preponderance of empirical evidence from legal, psychological, and media research that shows eyewitness identifications are often unreliable. Reasons for incorrect eyewitness identification include the eyewitness' motivation to exaggerate or lie about the identification, poor lighting and other environmental conditions that impede accurate observation of the offender, impaired eyewitness perception and observation due to emotions and biases, and flawed police means of leading eyewitnesses to suspect identifications. Crime investigators must operate under the knowledge that physical evidence found at the crime scene and interpreted by forensic experts is usually more significant than information obtained by questioning witnesses. Those who supervise investigations must ensure that investigations do not fall into the trap of relying upon or making other evidence fit an eyewitness identification. Further, any police procedure for obtaining an eyewitness identification must be structured and protected to ensure objectivity and the absence of any pressure or suggestion to focus on particular mug shots or persons in a lineup.