San Francisco supervisors using messaging app that lets texts vanish

An encrypted messaging app that allows users to delete their texts automatically after just a few seconds has become a favored way of communicating among some San Francisco supervisors and their aides, raising questions about whether technological advances are subverting public-records laws.

The app, Telegram, was created by a Russian entrepreneur and claims to be 100 percent encrypted. It is one of several apps, including Snapchat, Wickr and Frankly, that offer self-destructing messages.