The problems of criminal investigations without witnesses

Abstract

This academic article aims to analyze the challenges of criminal investigations in cases where no eyewitness testimony is available. When a criminal offense occurs, investigators are the first actors in the criminal justice process responsible for establishing the facts surrounding the alleged offense. In practice, investigators tend to place greater emphasis on eyewitnesses or direct witnesses than on circumstantial evidence, even though circumstantial evidence may be used to establish criminal liability. However, proving an offense through circumstantial evidence requires the collection of multiple forms of evidence that are sufficiently interconnected and persuasive to satisfy the court beyond a reasonable doubt. Since circumstantial evidence does not directly establish the facts in issue, investigators must possess the skills and expertise necessary to formulate investigative strategies and effectively link relevant evidence together.

The study finds that a lack of knowledge and understanding among investigators may adversely affect the effectiveness of evidence collection, particularly in cases involving complex evidence, time-sensitive circumstances, or specialized technical knowledge. Such deficiencies may lead to shortcomings in the investigative process, resulting in insufficient evidence for the court to establish guilt and impose criminal sanctions. Consequently, offenders may evade punishment, while victims may be deprived of appropriate remedies and justice.

The author recommends that the Royal Thai Police assign the Legal Affairs and Case Divisions within each Provincial Police Bureau to undertake the following measures: (1) develop investigation manuals tailored to the types of criminal cases occurring within their respective jurisdictions; (2) compile documentation of common deficiencies in investigation files to serve as case studies for investigators; and (3) establish a committee-based investigation model for significant cases or cases involving severe penalties. These measures would enhance investigative competence, improve the quality of criminal investigations, and strengthen the effectiveness of the criminal justice system.