Any evidence found at a fire scene is collected by SOCO's and passed down the chain of custody to the Forensic Scientists back in a forensic laboratory for further analysis. The job of the Forensic Scientist is primarily to find detailed factual evidence from the trace evidence they are provide by analysing it in great detail with advanced techniques; an example would be taking a blood sample and doing DNA profiling techniques in order to be able to use against that of a suspects to prove whether or not their blood was at the scene.Forensic Scientists are involved in the analysis of evidence, recording of findings, and collecting of trace evidence found at a crime scene or accident. They use specialist analysis techniques like Mass Spectrometry, Gas Chromatography, DNA Profiling, and Cyanoacrylate Fuming where appropriate in order to analyse chemical, biological and physical evidence. The results from these findings will later be provided to a jury in court to prove the guilt or innocence of a suspect.
Finding out a suspects blood was at a scene from these detailed analysis techniques doesn't prove their guilt as such it only proves that their blood was at the scene of the fire which could have just been that they were in the scene before the fire and cut themselves. It is only when it comes to interviewing the suspects that the evidence against them to prove their guilt can build as if they state they've never been to the crime scene but their blood is proven to have been there then their story is questionable. Along with all the other evidence found at a scene that gets sent to a forensic laboratory including perhaps fire accelerants found at the scene and a suspects clothing that may be found to have the same accelerants present on them a case can begin to build against the suspect.
The Forensic team will set about also identifying the causes of the blaze based upon the chemical residue/evidence collected at the scene. They will use Gas Chromatography and Mass Spectrometry in order to separate out all the elements of a compound so as to compare with elements found on other evidence to begin to help build a case against a suspect. They may also be required in cases relating to/or involving drugs or alcohol to do a Toxicology examination of the chemical evidence they receive so as to identify the specific toxins in the samples. In a fire investigation it is very rare a toxicologist is required for anything more than expert advice on some aspects of poisonous gases,
Forensic Scientist play a vital role in the fire investigation process as they become in possession of all the evidence for the case and if no solid evidence is found from the evidence on the scene or the evidence becomes contaminated, damaged or destroyed in the labs then the whole case is void. The Forensic Scientist will liaise with the police (to provide updates on what has been found in the results), the pathologists (to determine exact cause of death of victims or for pathologists to highlight specific chemicals the team is to look out for as they may have been the cause of death), and the fire/police investigators on the case so they can make decisions on how to proceed with the case.
