The New York attorney general, Eric T. Schneiderman, on Saturday opened an investigation into a company that sold millions of fake followers on social media platforms, some of them copying real users' personal information. The company, Devumi, and its sale of automated followers to a swath of celebrities, sports stars, journalists and politicians, was detailed in a New York Times article published earlier on Saturday. At least 55,000 of its "bot" accounts used names, pictures, hometowns and other details taken from people on Twitter. The real users hailed from every U.S. state, including New York, and dozens of countries. "Impersonation and deception are illegal under New York law," Mr. Schneiderman wrote. "We're opening an investigation into Devumi and its apparent sale of bots using stolen identities." Tens of millions of fake accounts have been deployed to defraud businesses, influence political debates online and attract customers. Social media companies, including Twitter and Facebook, have drawn intense scrutiny for not taking greater steps to weed them out. Mr. Schneiderman ... has brought a series of cases focused on the emerging world of online fraud, impersonation and abuse. In December, he began an investigation into how the Federal Communications Commission was flooded with millions of fake comments on a proposal to scrap so-called net neutrality rules. Many of the comments used names and addresses borrowed from real people, almost always without their knowledge.