U.S. Sen. Al Franken began Tuesday’s Senate hearing on mobile privacy with Apple Inc. and Google Inc. by calling the companies “brilliant,” but by the end he remained anything but convinced that the two tech giants are taking customer privacy seriously enough.

“People have a right to know who is getting their information and a right to decide how that information is shared and used,” Franken said at the conclusion of the hearing. “I still have serious doubts that those rights are being respected in law or in practice.”

Franken’s hearing — his first as chairman of the new Privacy, Technology and the Law Subcommittee — was sparked in part by outcry over a report last month that Apple was storing detailed-location data on users’ phones. Google’s Android phones collect similar location data.

Apple and Google representatives defended their privacy policies at Tuesday’s hearing, saying that users opt-in to using location-based services and other data that’s shared with third parties.

“Apple is deeply committed to protecting the privacy of all of our customers,” said Guy “Bud” Tribble, Apple’s vice president of software technology. “Apple does not track users’ locations. Apple has never done so and has no plans to ever do so.”