Visual characteristics for sequencing of overlapping bloodstain patterns

Abstract The deposition sequence of overlapping bloodstain patterns can be valuable reconstructive information. A formal method for sequencing overlapping bloodstain patterns has yet to be published. We present a method for sequencing overlapping transfer and drip stains using visual characteristics. A survey was held amongst educated bloodstain pattern analysts to determine whether the newly acquired method will assist them in correctly sequencing these overlapping bloodstain patterns. Results showed a significant improvement of expert decisions: the percentage of overlapping stains correctly sequenced by participants increased from 57 to 79% using the visual characteristics defined in this study. These results suggest that a decision support system can be built, which helps investigators at the crime scene to sequence overlapping bloodstain patterns.