The son of Democratic presidential front-runner Joe Biden is under scrutiny for allegedly investing in a surveillance app used to spy on Muslims in China.

Hunter Biden, son of the 2020 hopeful, backed an investment firm that designed the spying apparatus, according to a new report released a day after the Trump administration criticized China for mass detention of Muslims.

The Intercept reported that Hunter's China-based investment firm, called Bohai Harvest RST, invested in the mobile app Face+++. The app was designed by the Chinese government to spy on its citizens, with heavy use reported in the western provinces to track the Uighurs, a Muslim minority.

The new information surfaced Saturday as the former vice president has come under scrutiny over his son's business ties to the Ukraine.

Hunter Biden served on the board of a Ukrainian energy company, Burisma Holdings, during the time when the Obama administration was looking to take actions against Russia for invading Eastern Ukraine.

News reports show that the former vice president had threatened the president of Ukraine to fire a prosecutor involved in an investigation of Burisma.