Preserving Evidence

The new detective you are assisting is interested in finding out more about how the possibility of DNA analysis affects procedure at the crime scene and afterwards. Write a memo for his benefit, addressing the following issues:

Brief explanation of what DNA analysis is and how it can be used as evidence in criminal investigations.
Explain why extra caution must be exercised when collecting DNA analyzable evidence.
Discuss the precautions that must be followed to avoid contamination of evidence that may contain DNA evidence.
Describe the methods for collecting and storing DNA evidence.
Identify and discuss at least one controversial issue connected to the collection and/or use of DNA evidence.