Info about use: 
we are a company that analysis blood left on the scene of the crime.
our company motto is every drop  tell a story.  The general role of the Bloodstain Pattern Analyst in a criminal investigation is to assist in the reconstruction of those events of an alleged incident that could have created the stains and stain patterns present at a crime scene.

when I get to the crime scene I follow this  steps.

step 1: first your look for any and all blood left at the scene. 

step 2:  photography  the blood the has been found at scene. (Do not touch any of the blood, before taking the picture.)

step 3: now you collect  a simply of the blood.