If you find yourself in a situation where you have been accused of a crime, it goes without saying that you hope the crime scene and evidence were properly handled. However, there are times that Pennsylvania crime scene technicians could make mistakes or contamination could occur that might taint evidence. This is something that simply cannot occur. It is a violation and a major issue within the criminal justice system.
Forensic Magazine explains that contamination of a crime scene ruins evidence and puts the prosecution's case in jeopardy. It also can be damaging to you as the defendant if your defense team does not learn of the contamination. If they do not know about it, then they cannot fight it in court.
Essentially, contamination is mainly due to people entering a crime scene. Anyone going into a crime scene could introduce contaminates. Mishandling of evidence also can create issues. It is important that a crime scene technician does everything possible to keep a crime scene secure.
The main way to do this is to close off the space and not allow anyone in who is not vital. It also means following protocol when collecting evidence and in entering a scene. In addition, anything in a scene, even a contaminate must be properly labeled and handled. Even booties worn at the scene needs collected and stored properly for later testing.
Sometimes contamination occurs due to first responders. They come into a scene to treat the victim and focus on the victim and not the scene. A crime scene technician should always account for all contaminates left behind by first responders.
This information is for education and is not legal advice.