In 2008, California Governor Jerry Brown enacted a comprehensive familial DNA policy, allowing law enforcement to use the DNA of a relative to track down a suspect.

Critics of this approach have voiced concerns about ethics and privacy, but it has occasionally proved successful when it comes to solving gruesome crimes. 

For more on the role familial DNA can play in an investigation, Take Two spoke to David Kaye, a professor of law at Penn State and an expert on scientific and forensic evidence.

Click the blue audio player to hear the full interview.