Research has established that factors known to influence eyewitness memory are not commonly understood by laypeople, judges, or attorneys. Often neglected in these studies is the group responsible for the collection of eyewitness evidence: police officers. It is important to identify what police officers understand about eyewitness factors because false identifications are the leading cause of wrongful convictions and police often play a critical role in collecting eyewitness information. In Study 1, officers in nine California Orange County Police agencies were surveyed about police lineup and identification procedures to assess the overlap between current police practices and "best practices." Department procedures deviated from "best practices" in three major areas: no agency utilized a double-blind safeguard to prevent inadvertent communication to the witness, no agency shuffled photo lineup orders for different witnesses, and no agency presented lineups sequentially. In Study 2, a questionnaire about various eyewitness-related factors known to influence eyewitness accuracy was used to compare the beliefs of police officers from one agency to college students. Overall, police officers did not score more proficiently than students. Because of direct involvement, training, and experience, officers were expected to demonstrate an advantage over students on the role of 'system' variables that are under police control (e.g., lineup procedures). However, no significant differences were found between officers and students on system variables, whereas students outperformed officers on the role of 'estimator' variables, factors that are not controlled by the police (e.g., features of the crime such as level of violence). Results from the two studies suggest that officers have a limited understanding of factors known to influence eyewitness accuracy, and that knowledge of these factors is not part of current training of officers, highlighting the need for improved guidelines and training. If appropriate guidelines are put into place and police officers become more aware of factors that influence eyewitness reliability, officers will be more likely to collect unbiased evidence from eyewitnesses and consequently the likelihood of a misidentification will be reduced.