WHAT DID BAIN REALLY SAY? A PRELIMINARY FORENSIC ANALYSIS OF THE DISPUTED UTTERANCE BASED ON DATA, ACOUSTIC ANALYSIS, STATISTICAL MODELS, CALCULATION OF LIKELIHOOD RATIOS, AND TESTING OF VALIDITY

摘要

This paper presents a preliminary analysis of the disputed utterance in Bain v R [2009] NZSC 16. A likelihood ratio is calculated as a strength-of-evidence statement with respect to the question: What is the probability of getting the acoustic properties of the disputed utterance if Bain had said "I shot the prick" versus if he had said "I can't breathe". In particular, an acoustic and statistical analysis is conducted on the first segment of the second word to estimate the probability of getting the acoustics of this segment if it were a postalveolar fricative versus if it were a palatal fricative. The validity of the system is tested and ways to improve the analysis are discussed.