Police investigators typically use a variety of methods and techniques to investigate crimes that have a significant impact on determining an offender's perpetrator, arrest, and/or confession. Qualitative research. Qualitative research is a type of research methodology that focuses on exploring and understanding people's beliefs, attitudes, behaviors, and experiences through the collection and analysis of non-numerical data. It seeks to answer research questions through the examination of subjective data, such as 3. Adaptation. Investigations evolve and can change direction when you least expect it. Thus, investigators must remain flexible and open-minded to the changing needs of the investigation, seizing new opportunities as they arise – without focusing on a single line of investigation at the expense of all . 4.