ABSTRACT
It is an established fact that laboratory investigations involving biological fluids play a vital role in crime investigations Blood as a source of evidence associated with crime, can provide valuable information that may solve the case. Proper collection, preservation and dispatch of this crucial evidence to the Forensic Science Laboratory is hence very essential. Improper collection and preservation can weaken or destroy a potential source of facts in a case. Many times the suspects may hide valuable blood stain evidence either on the object or the clothes in different conditions which may adversely affect the investigation. Hence, proper collection and preservation of blood stain is of paramount importance, as it may provide a strong link between an individual and a criminal act. The present study was undertaken to find out the maximum duration for which blood grouping is possible when the stains are exposed to varied environmental conditions.