Law-framed reasoning process: integrating mobile phone data in police investigations in China

The increasing involvement of digital devices, such as mobile phones, in criminal activities is adding challenges to police investigators’ capacity to identify and trace associated digital data. Forensic science research has underscored the necessity of understanding the cognitive processes involved in digital data analysis, as contextual information introduces interpretive uncertainties that impact the credibility of evidence. Therefore, this study explores investigators’ decision-making around how mobile phone data (and evidence) is used in investigating generic crimes from the perspective of front-line officers in China. This study employs a qualitative approach involving interviews with 29 police officers and 5 prosecutors to explore their perspectives on how front-line police investigators evaluated and interpreted mobile phone data. Findings reveal that mobile phone data was interpreted alongside all other case information. In this process, investigators’ knowledge of analysing mobile phone data was informed primarily by precedence. Investigation experience and investigators’ comprehension of judicial practices resulted in anticipation of the high probative value of interview evidence in criminal justice proceedings, and this understanding directed the interpretation and presentation of mobile phone data (and evidence). Since interview evidence was considered to be of prime importance in police investigations, it determines whether and what part of phone evidence was considered relevant to the investigation. This reliance on interview evidence introduces potential cognitive biases and uncertainty by way of focusing on selective or partial phone data, rather than an independent and comprehensive forensic examination isolated from information sources that may introduce biases.