Establishing phone-pair co-usage by comparing mobility patterns

Area of Science:

• Digital Forensics
• Mobile Device Analysis
• Statistical Modeling

Background:

• Establishing common phone usage is crucial in forensic investigations.
• Existing methods may lack transparency or real-world validation.

Purpose of the Study:

• To present a transparent, validated method for assessing if two phones were used by the same individual.
• To quantify the evidential strength using a likelihood ratio based on cell tower data.

Main Methods:

• Utilizing time and location data from mobile phone cell tower registrations.
• Employing logistic regression for hypothesis discrimination (same vs. different user).
• Applying kernel density estimation for likelihood ratio calculation.

Main Results:

• The method demonstrates good performance across various modeling choices.
• The approach shows robustness even with limited or lower-quality data.
• Validation on real-world data supports practical application.

Conclusions:

• The presented method offers a transparent and reliable tool for forensic investigations.
• This technique can effectively assess the evidential weight of shared phone usage.
• The study paves the way for practical court application of cell tower data analysis.