In some criminal cases, the only evidence available when it comes time for a trial is eyewitness testimony. In these cases, a witness will testify to what they allegedly saw or heard -- something that they personally experienced. In some cases, eyewitness testimony is all it takes for the prosecution to get a criminal conviction. However, in many cases, there will be some articles of physical evidence that need to be preserved for presentation in court. So, who collects and documents physical evidence from crime scenes in Fresno County?
The Fresno County Sheriff's Office has a Crime Scene Unit staffed with Identification Technicians. These individuals are the ones who respond to crime scenes to collect and document physical evidence. They do this by taking digital photographs, tagging items with identification numbers and collecting fingerprints, among other things.
The people who work with the Crime Scene Unit are highly trained. Most of them go through hundreds of hours of training in order to learn about and keep up to date with the latest technological advances and evidence collection techniques. According to the Fresno County Sheriff's Office, there are nine people who make up the Crime Scene Unit, and all of them are qualified to testify as expert witnesses.
However, a sound criminal defense approach will probably include attempts to poke holes in the testimony of even the most competent of prosecution witnesses. Identification Technicians with the Crime Scene Unit may be highly trained expert witnesses, but they aren't infallible. If there are any mistakes made in the collection of physical evidence or in maintaining solid documentation of the chain of custody for these items, it may be possible to get the potential evidence suppressed.