Often by the time police detectives arrive at a murder scene, numerous Fire Depa

Often by the time police detectives arrive at a murder scene, numerous Fire Department and EMS personnel as well as patrol officers have been all through a crime scene and touched numerous things. It is not that they were being intentionally sloppy or that they did not care about preserving the crime scene. These individuals had a different priority when they entered the scene. Preservation of human life comes first, and these first responders had a legitimate need to enter, verify a death, check for additional injured persons, suspects, and the like. That being said, everyone who entered took something into the scene and, when they left, they took something from the scene. Debris from their shoes may have been deposited in the crime scene, or debris may have been picked up and removed from the scene on their shoes. Fibers may have come off their clothing, or hair, dead skin, etc., may have remained at the crime scene. Did they open doors, turn on or turn off lights, move items around, put the phone back on the receiver, etc.? These are all valid questions and things to be considered when working a crime scene. After reviewing the reading indicated above, provide a thorough response to each of the following:
In your original post, answer the following:
Explain the difference between contamination and cross-contamination.
Describe what a standard of comparison is and create a fictitious scenario in which you would need one for evidentiary value. Please provide sufficient detail in your scenario to justify the use of a standard of comparison.
Imagine that you discover a sheet with what appears to be blood and semen on it at a crime scene. Describe the collection, storage, and management of this evidence.
Before you begin, be sure to review the following resources:Crime Scene Investigation Download Crime Scene Investigation, NIST.org, Ensure Contamination Control, pages 15-16 and 38-49