Wrongful Cold Case Homicide: When Convictions become Cold Cases

Cold case homicides are cases in which the homicide remains unresolved for an extended period of time, usually two years, typically due to insufficient evidence, lack of viable leads, or limitations in forensic technology at the time of the original inquiry. A growing body of academic research on cold case homicide has highlighted the issues of wrongful homicide convictions and miscarriages of justice in the global context. Building on this work, I recently conducted a global comparative study (GCS) on policing policies, procedures and practices to solve/investigate cold case homicides. One surprising problem to surface from this research is some homicides appear solved in legal terms while remaining unsolved in substantive terms. These cases are called wrongful cold case homicides, and this is an emerging concept in which a homicide investigation results in a conviction, yet justice is not served because an innocent person is punished while the real perpetrator remains unidentified. Although these cases do not appear in official cold case registries, they remain, in operational terms, unsolved murders. The overarching aim of my research is to identify the systematic causes of wrongful cold case homicides and consider how the criminal justice system proceeds with the reinvestigations of these cases.

To develop a robust understanding of these issues, it is important to consider what related research has revealed. In the criminal law literature, research on cold case homicide has largely focussed on traditional cold case homicides, often referred to as Absolute Cold Case Homicides (ACCH) or Conventional Cold Case Homicides (CCCH), in which crimes were committed conventionally for individual gains such as love, property and domestic violence. These homicides were reported to the police, investigated but remain unsolved. Other types of cold case homicides, usually called Non-Conventional Cold Case Homicides (NCCCH), are relatively rare, and include No Crime Cold Case Homicides (NCCCH), Unreported Cold Case Homicides (URCCH), Under Investigation Cold Case Homicides (UICCH), Cold Case Homicides of Political Unrest (CCHPU), Cold Case Homicides of Extrajudicial Killings (CCHEJK), Illegitimate, Unjustified and Unexplained Military Cold Case Homicides (IUUMCCH), and Wrongful Cold Case Homicides (WCCH). All of these types of cold homicides remain underexplored due to systemic problems in the criminal justice system, and a lack of academic and media attention, and public awareness. The systemic problem refers to structural weaknesses within the criminal justice system that prevent crime reporting, complaint registration and investigation, lack of institutional accountability, and the absence of clear and coherent justice system policies. While such issues may be less prevalent in western jurisdictions, they are more commonly observed in Pakistan. While this study is a comparative global perspective across the UK, US, Canada, Pakistan, Australia, and New Zealand, Pakistan is specifically highlighted because the systemic challenges associated with non-conventional cold case homicides including underreporting, compromised investigative mechanisms, and limited institutional accountability are more visibly pronounced there, making it a particularly important case for comparative analysis. Drawing on emerging typologies of cold case homicides, these types have received little to no academic attention, leaving significant gaps in understanding unsolved homicides.

As noted above, a wrongful cold case homicide can be understood as a case in which:

• An innocent individual is investigated, charged, convicted, imprisoned, and later acquitted or exonerated
• The actual perpetrator remains at liberty
• Justice has not been substantively served
• The case is not formally categorised as a cold case despite remaining factually unsolved.

While specific, comprehensive data on the exact number of exonerated murder cases that officially become "cold" is not available in any jurisdiction, data from established wrongful conviction registries provide some insight into the prevalence of wrongful cold case homicide. Studies and records from the National Registry of Exonerations, for example, suggest that a high number of wrongful homicide convictions go cold in the US. Likewise, the Innocence Project has highlighted that in only about 50% of DNA homicide exonerations, the real perpetrator is eventually identified. This alarming figure warrants concern about the credibility and effectiveness of the US criminal justice system and suggests that urgent reform is required to provide justice to those waiting for many years and decades. It is also the moral responsibility of the state, in general, and the justice system, in particular, to punish those responsible for serious crimes. In Pakistan, when an individual is exonerated by the Supreme Court of Pakistan in a murder case, the case is typically considered concluded, and there are no known instances in which law enforcement agencies have reopened the investigation or initiated proceedings against a new suspect. Pakistan is therefore an important jurisdiction in this comparative study because it provides insight into how wrongful cold case homicides are addressed within a criminal justice system where institutional limitations, lack of reinvestigation, and absence of criminal case review commission remain significant concerns. Taken together these findings point to a clear gap in criminal law policy that demands immediate and decisive attention.

Drawing on the findings from my GCS examining policing practices across multiple jurisdictions, is clear that when a wrongful homicide conviction occurs, a legally closed homicide case can enter a blind spot. In wrongful cold case homicides, wrongful convictions create a “blind spot” because once an innocent is acquitted, the case is institutionally and psychologically treated as unsolved. A significant amount of time has usually passed since the murder: evidence may have been lost or destroyed, witnesses may have died or relocated, and investigative effort is severely minimised. In this situation, the criminal justice system’s confidence to identify the real offender is often at its lowest, while the victim’s family may become disengaged or pessimistic, sometimes continuing to believe the acquitted individual was the true offender. These dynamics are compounded by cognitive biases like tunnel vision that discourage revisiting earlier assumptions. Consequently, alternative suspects remain unexplored, new leads are deprioritised, and the real perpetrator remains at large, leaving the case effectively removed from active investigation and creating a systemic “blind spot” in criminal justice processes.

Another issue concerning officially declared wrongful homicide convictions by the justice system is the phenomenon of wrongful acquittals. In some instances, convictions are subsequently overturned and transformed into acquittals due to corruption, including bribery, threats against the victim’s family, political interference, or the influence of powerful societal actors. Although the criminal justice system ultimately records these cases as wrongful convictions, they may more accurately be understood as wrongful acquittals, as the victim’s family may continue to believe that the acquitted individual is the true offender. In such cases, the integrity of the judicial process is fundamentally compromised, resulting in outcomes that fail to reflect the merits of the evidence. A particularly troubling consequence of these dynamics is that, once an acquittal is secured, the principle of double jeopardy prevents a person from being tried twice for the same offence especially in the US and Pakistan, leaving the case permanently unsolved. While such occurrences appear to be relatively rare within Western jurisdictions, they are considerably more prevalent in Pakistan.

Across common law jurisdictions, the effect of a wrongful acquittal in a murder case where the real offender remains unknown is shaped by the doctrine of double jeopardy, though modern reforms create important differences. For example, in the United Kingdom, Part 10 (sections 75–83) of the Criminal Justice Act 2003 allows for the quashing of an acquittal, a person may be retried for serious offences like murder if “new and compelling evidence” emerges, meaning the case can effectively be reopened despite initial finality. Similar qualified exceptions exist in Australia and New Zealand, for example, statutory double jeopardy reforms (2005–2011) in Australia across several states, and sections 376–378 of the Criminal Procedure Act 2011 in New Zealand, in which statutory reforms allow retrials in limited circumstances, reflecting an academic shift toward prioritising factual accuracy over absolute finality.

Canada adopts a hybrid approach and protects against double jeopardy under section 11(h) of the Canadian Charter of Rights and Freedoms: acquittals are generally final, but may be overturned on appeal for legal error, potentially leading to a new trial. By contrast, the United States and Pakistan maintain among the strictest models, under the Fifth Amendment in the US, where an acquittal is final and retrial is barred regardless of new evidence (subject only to the separate “dual sovereignty” doctrine). Pakistan retains a more classical position rooted in its Constitution and Criminal Procedure Code, where an acquittal operates as a complete bar to further prosecution for the same offence.

Wrongful cold case homicides are the most complex and difficult among all types of cold case homicides and may never be solved. In principle, when an accused person is acquitted in a murder case and the true offender remains unidentified, the case is reverted to cold case status, allowing for continued investigation. In practice, however, particularly in jurisdictions such as Pakistan and the United States, such cases often enter a highly complex and resource-intensive phase. During this stage, criminal justice agencies may prioritise other cases with a higher likelihood of resolution, reflecting a degree of institutional pessimism toward wrongful or unresolved homicide cases.

The recognition of wrongful cold case homicide carries significant implications for criminal justice policy and policing practice. First, it challenges the reliability of clearance rates as indicators of investigative effectiveness. A case recorded as solved may remain substantively unresolved. Second, it highlights the necessity of a systematic post-conviction review process capable of reassessing evidential integrity. Finally, it emphasises the importance of interdisciplinary collaboration among investigators, forensic scientists, intelligence analysts, and legal scholars. Global law enforcement agencies in the US, UK, Canada, Pakistan, Australia and New Zealand are in the process of establishing specialised cold case units. However, these units require the development of comprehensive datasets that include all types of cold case homicides in order to facilitate a more systematic and holistic understanding of the cold case problem. Current datasets within established cold case units primarily include only conventional cold case homicides, while other categories remain underrepresented or excluded.