Bloodline Detectives focuses on familial DNA investigation, a search technique which uses genetic material from relatives to track down a suspect to solve violent crimes.
Each episode shows detectives from all over the world solving cold cases by using the DNA of family members and how that additional DNA information is revolutionising genetic profiling to solve criminal cases.
Interviews with family members, police, and others who help solve cold cases by the use of Familial DNA. When DNA is left at crime scene, and the usual ways of identifying the suspect leads no where, Familial DNA comes in to play. Familial DNA is taking the DNA from the crime scene and using DNA that people have submitted to genealogy sites to see if there is someone who is a close match. From there genealogist can figure out who the suspect should be, and police can then make an arrest. Piers Gibbon is the narrator for the show.