Since the arrest of the "Golden State Killer" eight years ago, genetic genealogy has been used to solve hundreds of cold cases across the the United States and Canada.

But paying for the powerful forensic tool is not straightforward, and many law enforcement agencies are relying on crowdfunding to afford it.

"I think it is amazing that members of the public are willing to donate money to help solve these cases," said one genealogy expert. "But it's not a sustainable criminal justice system."