Fingerprints can be found on most pieces of Physical Evidence, meaning that Forensic Analysts can check things such as glasses, furniture and even the weapon if found. Fingerprints will often be identified at the crime scene, and then taken back to the Lab in order to either be enhanced or simply to run the print through the fingerprint database in order to determine who the print belongs to.
DNA can be found in the form of blood, saliva, semen, skin cells, or even Hair, if there is a root still attached to it. This evidence can be analysed by the team by investigating the genetic factors of the sample, and running it against the DNA database in order to find a potential match.
Each Forensic Analyst will have a speciality on which they would work, for example, a computer which needs to be analysed would be taken to an expert in Forensic Computing, and something which has been burnt would be taken to a combustion expert.
The OJ Simpson Case
During the OJ Simpson case, much of the evidence collected from the scene was never entered into the Chain of Custody, meaning that the evidence was missing for a long time until found. This then, in turn, meant that the evidence could not be used, as there was no proof that the evidence had not been tampered with. This occurred most famously with a Vile of OJ's blood which was not only labelled incorrectly but went missing for hours before being found, meaning once again that the validity of the evidence was brought into question.