Bacterial pathogenesis is the process by which bacteria infects a host. Not all bacteria are pathogens but some of them have the ability for pathogenesis. Many bacterial Infection forms biofilms with which its pathogenic nature increases. Certain pathogens like Pseudomonas syringe injects virulence in plant host causing diseases. For the Diagnosis of Pathogenic microorganisms Direct Examination and Techniques includes Immunofluorescence, immuno-peroxidase staining, and other immunoassays may detect specific microbial antigens. Genetic probes identify genus- or species-specific DNA or RNA sequences. Forensic evidence involves application of forensic science, technology or "forensics", in order to identify the scene of an accident, specific objects from the trace evidence and often at a crime scene. It is usually submitted to court, which are obtained by scientific methods like by blood test, DNA test.