Services like ancestry.com and 23andme are increasingly popular among Americans. According to ABC News, genealogy is now the second most popular hobby among Americans (second to gardening). News stories out of Miami and New Orleans and Idaho City now chronicle the tale of a genealogical quest that ended in a criminal investigation. In these cases, law enforcement sought DNA samples collected by Ancestry.com and 23andme to compare to DNA evidence at a crime scene.
source

What was that again lol
Police used ancestry.com to just find the serial killer/rapist ..the Golden State killer