Breaking with trends in forensic dating: A likelihood ratio-based comparison approach

Area of Science:

• Forensic Science
• Biochemistry
• Analytical Chemistry

Background:

• Determining the age of bloodstains is crucial in forensic investigations.
• Existing bloodstain dating methods are limited by environmental and circumstantial variability.
• Lack of suitable analytical techniques is not the primary barrier to bloodstain aging.

Purpose of the Study:

• To develop a novel framework for estimating the age of bloodstains in forensic scenarios.
• To overcome limitations of current absolute age estimation methods.
• To provide a practical approach for situating forensic traces in time.

Main Methods:

• Utilizing a likelihood ratio assessment to compare evidence decomposition with reference materials.
• Employing supervised aging techniques to generate reference bloodstain samples.
• Developing a case-by-case dating procedure tailored to specific blood traces.

Main Results:

• Demonstrated the feasibility of a new framework for bloodstain age estimation.
• The proposed method accounts for variability in degradation kinetics.
• The approach limits the adverse influence of external factors on age estimations.

Conclusions:

• The novel framework offers a more reliable method for bloodstain dating in forensic science.
• This approach allows for time-centered questions to be answered in real forensic scenarios.
• The method is suitable for future crime scene implementation.