Bloodstain pattern || Well-Enlightened

What is a bloodstain pattern? correct answers A physical, geometric image created by blood contacting a surface, or by a surface contacting blood What does BPA stand for? correct answers Bloodstain Pattern Analysis What can an investigator learn from the analysis of a blood spatter? correct answers -type and velocity of a weapon -number of blows -handedness of assailant (right or left) -position and movements of the victim and assailant during and after the attack -which wounds were inflicted first -type of injuries -how long ago crime was committed -whether death was immediate or delayed Impact surface considerations correct answers -course surfaces cause irregularities in patterns -blood may break up on impact, and may follow the contour of a surface -impact angles and directionality become less reliable as a surface becomes more porous How is blood evidence detected at a crime scene? (Light source) correct answers Investigators may use a high-intensity light or UV lights to help them find traces of blood as well as other bodily fluids that are not visible under normal lighting conditions How is blood evidence detected at a crime scene? (Blood reagent tests) correct answers These tests, aka PRESUMPTIVE TESTS, are used to detect blood at crime scenes based upon the properties of hemoglobin in the blood. Further tests at the crime lab can determine if it is human blood or not. Phenolphthalein correct answers A chemical that is still utilized today and is usually referred to as the KASTLE-MEYER test and produces a pink color when it reacts with hemoglobin Hemastix correct answers A strip that has been coated with tetremethylbenzidine (TMB) and will produce a green or blue-green color with the presence of hemoglobin How is blood evidence detected at a crime scene? (Luminol) correct answers Used by CSI to locate traces of blood, even if it has been cleaned or removed. They spray the solution and look for reactions with the iron present in the blood, which causes a blue luminescence. A problem is that other substances may react, such as some metals, paints, cleaning products, and plant materials. Also can destroy evidence at a crime scene. How is blood evidence detected at a crime scene?(Fluorescein) correct answers This chemical is capable of detecting latent or old blood, similar to luminol. Ideal for fine stains or smears found throughout crime scene. After solution has been sprayed, a UV light and goggles are used to detect any illuminated areas, which appear greenish-white if blood is present. May react to many of the same things as luminol.