The data leak contains a wealth of personal information on roughly 61 percent of the US population. Along with home addresses, birthdates, and phone numbers, the records include advanced sentiment analyses used by political groups to predict where individual voters fall on hot-button issues such as gun ownership, stem cell research, and the right to abortion, as well as suspected religious affiliation and ethnicity. The data was amassed from a variety of sources—from the banned subreddit r/fatpeoplehate to American Crossroads, the super PAC co-founded by former White House strategist Karl Rove.

Deep Root Analytics, a conservative data firm that identifies audiences for political ads, confirmed ownership of the data to Gizmodo on Friday.

UpGuard cyber risk analyst Chris Vickery discovered Deep Root’s data online last week. More than a terabyte was stored on the cloud server without the protection of a password and could be accessed by anyone who found the URL.