What defines a cold case?

A cold case is defined as an investigation that remains unresolved after a significant amount of time has passed since the crime occurred. This typically means that, despite the initial investigative efforts, law enforcement has not been able to gather sufficient evidence to solve the case or make an arrest. Cold cases often arise from various circumstances, such as a lack of leads, witnesses, or physical evidence, making it difficult to proceed with the investigation effectively.

Over time, cold cases may be revisited by law enforcement agencies as new evidence or advances in forensic technology arise, which can potentially lead to new leads or solutions. Understanding the nature of cold cases is crucial for investigators, as they require different strategies from actively pursued investigations. The other options encompass situations that do not fit this specific definition: reopening a solved case, ongoing investigations, and cases with unresolved evidence do not capture the essence of a cold case.