At least some of the U.S. intelligence community purchases commercially available cellphone data containing location information from smartphone apps and uses that to search and track the movements of U.S. citizens without a grand jury subpoena or a court order, according to an unclassified memo.

The Defense Intelligence Agency told Sen. Ron Wyden of Oregon in a document made public on Friday that it “provides funding to another agency that purchases commercially available geolocation metadata aggregated from smartphones,” but it has only done so for “authorized purposes” five times in the past two-and-a-half years.