Earlier this week, we learned that the insanely popular mobile gaming app Pokémon Go requested full access to users' Google accounts when activated on iOS. Niantic said that it was a mistake, and the issue was corrected in an update for the app.

Yesterday, Sen. Al Franken (D-Minn.) sent a letter (PDF) to game creator Niantic asking the company to explain that issue as well as some of the other privacy choices in the game.

The letter notes that Pokémon Go collects profile and account information, location data, and data "obtained through Cookies and Web Beacons." The game also asks permission to do things like control vibration and prevent the phone from sleeping. Franken wants to know what information and functions exist to support and improve services, and what's being gathered for "other purposes."

Franken, the top Democrat on the Senate Privacy and Technology Subcommittee, also asks if Niantic would consider making more of the information gathering "opt-in" rather than requiring users to "opt out" if they don't want data collected. He also wanted to know what third parties The Pokémon Company shares information with, and what kind of parental consent is obtained with regards to the personal information of children.

The game has been downloaded about 7.5 million times in the US, Franken noted in a press release accompanying the letter. "While this release is undoubtedly impressive, I am concerned about the extent to which Niantic may be unnecessarily collecting, using, and sharing a wide range of users' personal information without their appropriate consent," stated Franken.

Franken wants the company to respond to his questions by August 12.