Americans were alarmed earlier this year when a Chinese spy balloon was shot down over U.S. soil, but that is far from China’s only efforts to collect information on the U.S. The nation uses intellectual property theft and cyber attacks to gather intel, and recently more evidence of physical evidence-gathering has come to light.

House Oversight Chair Rep. James Comer, R-Ky., and Subcommittee on National Security, the Border, and Foreign Affairs Chairman Glenn Grothman, R-Wis., sent a letter to Department of Defense Secretary Lloyd Austin and FBI Director Christopher Wray.