Final answer:
Jeffrey Dahmer was exposed as a serial killer in 1991, whereas the cases of Jennifer Thompson and Jean Gianini demonstrate complexities in criminal investigations and legal proceedings.
Step-by-step explanation:
Jeffrey Dahmer was discovered as a serial killer in the year 1991. His arrest exposed him as a culprit behind a series of grisly murders that spanned several years.
An analysis of the misidentification in the case of Jennifer Thompson shows how faulty eyewitness testimony can lead to the conviction of an innocent person, such as Ronald Cotton, showcasing the complexities within criminal investigations.
Conversely, the case of Jean Gianini in 1914 demonstrates the use of criminal evidence, such as a lost button, and psychological testimony in court proceedings, highlighting different facets of the legal system in handling crime.