Variations in the Impact Spatter Patterns due to Blunt Weapons Inflicted by Different Gender and Age Groups

Bloodstain pattern analysis makes use of the mechanics of bloodstains to estimate the time, nature and the sequence of events at the crime scene. In this study, a quantitative methodology was developed which includes manually calculating the average size of the bloodstains and the synthetic bloodstains to distinguish the impact stain patterns created by different gender and age groups using the two blunt weapons. Impact stains were created by hitting sponges soaked in blood and synthetic blood using a hammer and a cricket bat. A smaller bloodstain size was observed of the group of males aged between 18 to 30 years. Greater amount of spatter and the distribution of the blood spatter were observed with the bat as compared to hammer due to larger surface area of bat. Cast off patterns were studied and were observed to be produced only by the bat which can be attributed to its higher surface area. Results showed difference in the bloodstain diameter produced from human blood and synthetic blood evaluating if the synthetic blood is suitable for use, as well as variation in the average stain size between produced by the four groups using both the fluids.