In 2012, a man by the name of Luka Magnotta was arrested in Berlin for allegedly murdering a college student and posting a video of the act online. Before authorities began an international manhunt for the accused killer, a group of citizens had already contacted authorities with their concerns about Magnotta. Magnotta, they said, had committed acts of murder in the past -- but nobody listened, because he'd only "murdered" a pair of cats.
As a new report in Rolling Stone details, it was a ragtag team of hackers, investigators, activists and yes, pet-lovers, who first identified Magnotta, after they spent months trying to find justice for two innocent kittens that had been killed on camera. Motivated to uncover the person behind the grisly cat murder, the group worked together in online forums to gather detailed photographic analyses, metadata and precise estimations of their suspect's whereabouts that eventually led to his identification.
A number of the individuals who pursued Magnotta have remained committed to catching animal abusers in the aftermath of his case. Two of the investigators who discovered the killer later founded the Animal Beta Project, and are still working together to investigate animal cruelty discovered online. So far, they've been instrumental in several investigations and indictments.
You can read more about the dedicated pet-lovers and their investigation on Rolling Stone's website.