Which document type helps in understanding a suspect's previous charges?

The document type that helps in understanding a suspect's previous charges is crime lab reports. These reports are generated from the analysis of physical evidence collected during investigations. They often include details about forensic examinations, which can reveal a suspect's involvement in prior criminal activities based on evidence collected at different crime scenes. Crime lab reports are essential in establishing patterns of behavior or prior offenses, as they directly relate to the legal aspects of a suspect's history.

Other options, like personal diaries and social media posts, may provide insights into a suspect's thoughts or behaviors but do not systematically catalogue legal charges. News articles can report on crimes, but they may lack the specificity needed to understand a suspect's history with charges comprehensively. Crime lab reports, however, focus specifically on the forensic evidence and can provide a factual basis for understanding a suspect's previous legal issues.