U.S. federal investigators will probe Facebook’s planned $1 billion acquisition of the social photo-sharing network Instagram. Facebook has reportedly received a “second request” for information from the Federal Trade Commission, Reuters said Tuesday. Regulators will use the information to decide whether or not the purchase will infringe on U.S. antitrust laws. Facebook recently launched its own “Facebook Camera” application, which offers similar features to Instagram, but Instagram is, by far, the most popular photo-sharing service of its kind. It is unclear how long the investigation will take.