The Department of Justice is demanding Apple and Google hand over identifying information for over 100,000 users of the car modification app EZ Lynk. This subpoena, issued in March and April, seeks names, addresses, and purchase histories as part of an ongoing case against the app's developer for alleged Clean Air Act violations.

EZ Lynk, based in the Cayman Islands, is accused of selling 'defeat devices' that remove vehicle emissions controls. The company argues its app has legitimate uses like performance tuning and diagnostics. Its legal team contends the massive data request violates privacy and exceeds the case's needs, noting investigators can interview witnesses directly.

The government maintains the request is fair, citing already presented evidence from social media where users discussed removing emissions controls with EZ Lynk tools. This clash highlights growing tensions between law enforcement investigations and the vast troves of user data held by tech platforms, setting a significant precedent for digital privacy in regulatory enforcement.