Celia Blay, a British grandmother from Wiltshire who gained media attention for tracking down an online internet predator... In 2006, Blay learned that a vulnerable young woman had entered an online suicide pact with someone calling himself “Li Dao.” Blay intervened, and the woman abandoned the plan. But Blay kept investigating. She discovered multiple identities, including “Falcon Girl” and “Cami,” apparently being used by the same person. Behind them was William Melchert-Dinkel, a Minnesota nurse who posed online as a sympathetic young woman and befriended people contemplating suicide. Blay collected evidence, warned people online and pursued authorities across two countries. In March 2008, she contacted St. Paul police with information linking the predator to Minnesota. Investigators traced the accounts to Melchert-Dinkel. The resulting case connected him to Mark Drybrough, who died in England in 2005, and Nadia Kajouji, who died in Canada in 2008. His prosecution became a complicated, years-long legal battle, ultimately leaving in place his conviction for assisting Drybrough’s suicide. Celia Blay wasn’t a detective. She was a retired teacher who saw something terrifying happening online and refused to stop looking.