Abstract Latent fingerprints are a critical component of the evidence that is captured and analyzed from crime scenes and presented for convictions in court. Although fingerprint science has been used for many years in forensics, it is not without many criticisms and critiques from those that believe it is too subjective. Researchers from many disciplines have tried to refute this claim by completing experiments that would eventually lead to a fingerprint aging technique as well as providing statistical models and mathematical support. In this literature review, the research that has been widely published and talked about in this field was reviewed and analyzed to determine what aspects of the experiments are benefitting the study of degradation. By carefully combing through the methods and results of each study, it can be determined where future focuses should be and what disciplines need to be exploited for knowledge. Lastly, an important aspect of the experiments in recent years have depended on the collaboration with statistics so this evidence was examined to identify what models are realistic in determining error rates and likelihood ratios to support latent fingerprint evidence in court. After a thorough review, it is seen that although large strides have been taken to study the degradation of fingerprints, the day where fingerprints will be able to be definitively aged may be ways away. The current experiments have provided methods such as three-dimensional and visual parameters that could potentially find the solution, but also uncovered methods such as immunolabeling and chemical composition that face major challenges. From the statistically point of view, researchers are very close in developing equations that exploit the likelihood ratios of similarity and even calculate the various possible error rates. The evidence found in this review shows that science is one step closer to the age determination of fingerprints.

Serial killers have had a profound impact on the United States' most powerful law enforcement agency, the Federal Bureau of Investigation. Through a brief history of the FBI, the birth of the Behavioral Analysis Unit is highlighted and criminal profiling is realized as a tool to apprehend these serial killers. Four serial killer cases are presented as important representations to illustrate the contributions that were made to the FBI's investigatory procedure. As serial killings make up only one percent of the murders in the U.S. each year, it is still evident that these cases have had a profound impact on the U.S.'s top law enforcement agency. The FBI has been able to react to each case more effectively than the last. Constant learning on the job, as each impactful case happens within a short time span from the last, has been a necessity for investigators and has been a prime strength of the FBI. There is no way to tell when an individual will begin to commit serial murder, so while the FBI's methods are not perfect, the Bureau has been able to respond in full to each challenge a new serial killer case has presented and arrest the guilty party. Through an analysis of the criminal profile, stereotypes attributed to serial killers, and the application of forensic evidence to serial killer investigations, the impact of the investigations of these cases by the FBI is examined. A real world application of the FBI's recommended procedure for a serial killer investigation is spotlighted and analyzed to determine its practicality in modern-day investigations.