Visitors pass in front of the Huawei's stand on the first day of the Mobile World Congress in Barcelonaon on February 27, 2017 in Barcelona.

The FBI raided a Huawei lab in San Diego and set up a sting operation at CES in Las Vegas in January as part of a third investigation into the smartphone maker, according to a new report by Bloomberg Businessweek.

Last week, the U.S. Department of Justice charged Huawei and its chief financial officer, Meng Wanzhou, with an alleged violation of sanctions against Iran. It also charged Huawei for allegedly stealing trade secrets from T-Mobile. The newly reported third investigation similarly deals with trade secrets, but carries the added weight of federal regulations around technologies with the potential for use in defense.

It also sheds light on how far Huawei is willing to go for a competitive edge, and on the extent of FBI fact-finding operations involved in these investigations.