Hackers attacked I.R.S. requesting past tax returns of more than 100,000 people

More than 200,000 attempts to view the past returns using stolen information were made from February to mid-May. So 50 percent of them were successful. I.R.S. had stopped almost three million suspicious returns this year, after it paid $5.8 billion in falsely claimed refunds in 2013. Senate Finance Committee was notified of the actual breach. Officials opened the investigation. “We’re confident that these are not amateurs,” John Koskinen, the I.R.S. commissioner, said. In other words, it’s about the organized crime around the world with “extremely sophisticated criminals with access to a tremendous amount of data”.The agency sent letters to the taxpayers whose accounts had been compromised, and it will offer them free credit monitoring. The Get Transcript application which was used to gain access to the information was temporarily shut down.