Semester

Summer

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Forensic and Investigative Science

Committee Chair

Keith Morris

Committee Co-Chair

Tina Moroose

Committee Member

Evelyn Gonzalez

Committee Member

Tiffany Edwards

Abstract

Crime scene mapping is the process of measuring and fixing items present in the crime scene to obtain a detailed to-scale map of the scene as found by the crime scene investigators. When bloodstain patterns are present, investigators must analyze the bloodstains to assist in determining where the blood-shedding event occurred. The volume of origin is determined through a manual stringing method that is labor-intensive and destructive.

Technological advancements have been made in other fields, such as land surveying, and were adopted by law enforcement-related fields. These advancements include electronic terrestrial scanners, like the total station, and three-dimensional scanners, like the FARO® laser scanners. Both of these tools, combined with software, have proven helpful in speeding up the process of crime scene mapping. The 3D models of the scene allow investigators to better understand the spatial relationship between the evidence of interest, other pieces of evidence, and the area within which the evidence is located.

The goal of this research is to compare and contrast the repeatability and reproducibility of the NorthWest Instrument NTS03 Total Station and the FARO® FOCUSs 350 laser scanner when capturing bloodstain pattern evidence. The point clouds from the FARO® were uploaded into FARO® SCENE and FARO® Zone 3D software for analysis. The two (2) FARO® software were able to be compared during the preliminary analysis, but not the volume of origin analysis due to a software error. The total station data was not able to be uploaded and analyzed into FARO® Zone 3D due to the way the NorthWest Instrument NTS03 total station packaged the data points.

The preliminary analysis found that both FARO® software perform similarly and that the software measurements were dependent upon the area and circular shape of the ellipse. The volume of origin analysis found that, even though all software measurements were statistically different from the ground truth, both the FARO® Zone 3D and HemoSpat software analysis errors were within the accepted error range of 7.87 in. The bloodstain selection analysis found that 30 bloodstains should be selected for the volume of origin analysis in the FARO® Zone 3D software package to obtain repeatable and reproducible results.

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