What is a primary tool used by Cold Case Investigators to connect suspects with their relatives?

DNA evidence is a primary tool for cold case investigators due to its ability to provide a genetic link between a suspect and their relatives. This is particularly valuable in cases where traditional evidence may be lacking or where witnesses may not be available. DNA can be collected from various sources, such as blood, hair, or other biological materials left at a crime scene. If investigators are able to match this DNA to a suspect, they can further investigate the suspect's familial connections using genetic databases or ancestry testing.

This tool enables the establishment of familial relationships, which can open up new lines of inquiry, potentially identifying parents, siblings, or other relatives of a suspect who may have relevant information regarding the cold case. Additionally, advancements in DNA technology have increased the accuracy and reliability of DNA analysis, making it a critical component in modern cold case investigations.