Technical features built into Republican presidential candidate Sen. Ted Cruz’s popular “Cruz Crew” app are helping the campaign to gauge the attitudes of their supporters, and also to reach their supporters’ friends and contacts, according a report from the AP.

The app, which has been downloaded over more 60,000 times, reportedly goes further than most data-mining when it comes to collecting personal data. According to the AP:

His “Cruz Crew” mobile app is designed to gather detailed information from its users’ phones — tracking their physical movements and mining the names and contact information for friends who might want nothing to do with his campaign.

That information and more is then fed into a vast database containing details about nearly every adult in the United States to build psychological profiles that target individual voters with uncanny accuracy.

The Cruz app prompts supporters to register using their Facebook logins, giving the campaign access to personal information such as name, age range, gender, location and photograph, plus lists of friends and relatives. Those without a Facebook account must either provide an email address or phone number to use the app.

Other candidates are using similar cellphone apps to reach supporters’ friends and contacts.

Democratic Sen. Bernie Sanders’ app, “Field the Bern,” requires supporters to sign in using their Facebook account or an email address, and it also repeatedly asks to let the campaign track their movements until they answer yes.

So far, neither Donald Trump nor Hillary Clinton have deployed similar software, said the AP report.