The shock gloves immigration agents could soon use to control detainees and protesters worked so powerfully during a military exercise that participants felt intense pain, stopped fighting immediately and feared additional exposures, according to a previously unreleased Army study.

Immigration and Customs Enforcement leaders were aware of the findings before signing a $16.7 million contract to purchase 6,000 pairs of shock gloves in August, according to records obtained by the watchdog group American Oversight and shared with The Associated Press.

The shocks had a profound impact on Army employees who played the role of combative prisoners during the exercise, which took place at the military prison at Fort Leavenworth in Kansas in October 2024. The participants, several of whom were large-statured men, stopped resisting seconds after officers applied shocks by touching gloves to their skin, and were left with “fatigue, soreness and excessive apprehensiveness to being shocked again,” the study found.