Police close in on a robbery gang targeting people who buy and sell goods on Facebook Marketplace. The robbers are finally caught thanks to data captured by their electronic curfew tags. The data not only shows they weren’t at home, it also places them close to the scene of the crime.

Also in this episode, a father whose daughter was murdered by her abusive and controlling ex-boyfriend launches a phone app he hopes will help keep other young women safe. And the parents of a hit-and-run victim help trace the driver who knocked their son down. Show less