A Forensic Investigator is basically an Investigator that establishes evidence for litigation based on scientific methods. The Forensic Investigator can examine and establish both physical evidence and digital evidence.
What is Forensics:
Science + The Justice System = Forensics
The evidence that a Forensic Investigator produces is to be utilized in litigation, both civil and criminal. This means that a Forensic Detective can be in the employ of a government organization such as law enforcement or employed in the private sector. Both types of Forensic Investigators will often produce their evidence in litigation as “expert witnesses.”
A simple example of forensics can be seen with fingerprint matching or even matching a footprint pattern. A Forensic Investigator can establish a connection from an incident to an individual based on their fingerprint or shoe print and its discovery at a location. The Forensic Investigator can testify as an expert witness on how they connected the patterns to the individual that is the "subject" of the litigation. This can go even further, with the Forensic Investigator establishing connections using DNA or chemistry. In fact, there are thousands of methods Forensic Investigators can utilize to establish connections to individuals based on physical science.