List the five basic tasks that need to be completed in order to properly process of crime scene. what is the goal of each task?

. What happened?
 Was a crime committed? 
 If a crime was committed, how was it committed?
. Find and mark evidence
 Get an overall layout of the scene
. Evidence should connect victim to the crime, or perpetrator to the crime
. Avoid contamination of the evidence
. Evidence will be examined by a crime lab